diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index db8628c8a7..fe22af763f 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -544,7 +544,9 @@ en:
 
     dominating_topic: You’ve posted a lot in this topic! Consider giving others an opportunity to reply here and discuss things with each other as well.
 
-    get_a_room: You’ve replied to @%{reply_username} %{count} times, did you know you could send them a personal message instead?
+    get_a_room:
+      one: "You’ve replied to @%{reply_username} once, did you know you could send them a personal message instead?"
+      other: "You’ve replied to @%{reply_username} %{count} times, did you know you could send them a personal message instead?"
 
     too_many_replies: |
       ### You have reached the reply limit for this topic
@@ -707,7 +709,9 @@ en:
       topic_exists:
         one: "Can't delete this category because it has %{count} topic. Oldest topic is %{topic_link}."
         other: "Can't delete this category because it has %{count} topics. Oldest topic is %{topic_link}."
-      topic_exists_no_oldest: "Can't delete this category because topic count is %{count}."
+      topic_exists_no_oldest:
+        one: "Can't delete this category because it has %{count} topic."
+        other: "Can't delete this category because it has %{count} topics."
     uncategorized_description: "Topics that don't need a category, or don't fit into any other existing category."
   trust_levels:
     admin: "Admin"
@@ -2444,7 +2448,9 @@ en:
         regex_invalid: "The regular expression is invalid: %{error}"
         leading_trailing_slash: "The regular expression must not start and end with a slash."
       unicode_usernames_avatars: "The internal system avatars do not support Unicode usernames."
-      list_value_count: "The list must contain exactly %{count} values."
+      list_value_count:
+        one: "The list must contain exactly %{count} value."
+        other: "The list must contain exactly %{count} values."
       markdown_linkify_tlds: "You cannot include a value of '*'."
       google_oauth2_hd_groups: "You must configure all 'google oauth2 hd' settings before enabling this setting."
       search_tokenize_chinese_enabled: "You must disable 'search_tokenize_chinese' before enabling this setting."
@@ -3275,10 +3281,16 @@ en:
     email_reject_post_too_short:
       title: "Email Reject Post Too Short"
       subject_template: "[%{email_prefix}] Email issue -- Post too short"
-      text_body_template: |
-        We're sorry, but your email message to %{destination} (titled %{former_title}) didn't work.
+      text_body_template:
+        one: |
+          We're sorry, but your email message to %{destination} (titled %{former_title}) didn't work.
 
-        To promote more in depth conversations, very short replies are not allowed. Can you please reply with at least %{count} characters? Alternatively, you can like a post via email by replying with "+1".
+          To promote more in depth conversations, very short replies are not allowed. Can you please reply with at least %{count} character? Alternatively, you can like a post via email by replying with "+1".
+
+        other: |
+          We're sorry, but your email message to %{destination} (titled %{former_title}) didn't work.
+
+          To promote more in depth conversations, very short replies are not allowed. Can you please reply with at least %{count} characters? Alternatively, you can like a post via email by replying with "+1".
 
     email_reject_invalid_post_action:
       title: "Email Reject Invalid Post Action"
@@ -4613,7 +4625,9 @@ en:
     mass_award:
       errors:
         invalid_csv: We encountered an error on line %{line_number}. Please confirm the CSV has one email per line.
-        too_many_csv_entries: Too many entries in the CSV file. Please provide a CSV file with no more than %{count} entries.
+        too_many_csv_entries:
+          one: Too many entries in the CSV file. Please provide a CSV file with no more than %{count} entry.
+          other: Too many entries in the CSV file. Please provide a CSV file with no more than %{count} entries.
         badge_disabled: Please enable the %{badge_name} badge first.
         cant_grant_multiple_times: Can't grant the %{badge_name} badge multiple times to a single user.
     editor:
diff --git a/plugins/chat/assets/javascripts/discourse/components/chat-channel-settings-view.hbs b/plugins/chat/assets/javascripts/discourse/components/chat-channel-settings-view.hbs
index 5597f74a5c..e6ff9eb74e 100644
--- a/plugins/chat/assets/javascripts/discourse/components/chat-channel-settings-view.hbs
+++ b/plugins/chat/assets/javascripts/discourse/components/chat-channel-settings-view.hbs
@@ -62,7 +62,7 @@
     {{d-icon "info-circle"}}
     {{i18n
       "chat.settings.retention_info"
-      days=this.siteSettings.chat_channel_retention_days
+      count=this.siteSettings.chat_channel_retention_days
     }}
   </div>
 </div>
diff --git a/plugins/chat/assets/javascripts/discourse/components/chat-retention-reminder.js b/plugins/chat/assets/javascripts/discourse/components/chat-retention-reminder.js
index ec66766760..e2f77faf6b 100644
--- a/plugins/chat/assets/javascripts/discourse/components/chat-retention-reminder.js
+++ b/plugins/chat/assets/javascripts/discourse/components/chat-retention-reminder.js
@@ -32,7 +32,7 @@ export default Component.extend({
       days = this.siteSettings.chat_dm_retention_days;
       translationKey = "chat.retention_reminders.dm";
     }
-    return I18n.t(translationKey, { days });
+    return I18n.t(translationKey, { count: days });
   },
 
   @discourseComputed("chatChannel.chatable_type")
diff --git a/plugins/chat/assets/javascripts/discourse/controllers/create-channel.js b/plugins/chat/assets/javascripts/discourse/controllers/create-channel.js
index 00b9b8e0ae..299e0fc8bb 100644
--- a/plugins/chat/assets/javascripts/discourse/controllers/create-channel.js
+++ b/plugins/chat/assets/javascripts/discourse/controllers/create-channel.js
@@ -91,16 +91,29 @@ export default class CreateChannelController extends Controller.extend(
     const allowedGroups = catPermissions.allowed_groups;
 
     if (catPermissions.private) {
-      const warningTranslationKey =
-        allowedGroups.length < 3 ? "warning_groups" : "warning_multiple_groups";
+      let warningTranslationKey;
+
+      switch (allowedGroups.length) {
+        case 1:
+          warningTranslationKey =
+            "chat.create_channel.auto_join_users.warning_one_group";
+          break;
+        case 2:
+          warningTranslationKey =
+            "chat.create_channel.auto_join_users.warning_two_groups";
+          break;
+        default:
+          warningTranslationKey =
+            "chat.create_channel.auto_join_users.warning_multiple_groups";
+          break;
+      }
 
       this.set(
         "autoJoinWarning",
-        I18n.t(`chat.create_channel.auto_join_users.${warningTranslationKey}`, {
-          members_count: catPermissions.members_count,
+        I18n.t(warningTranslationKey, {
+          count: catPermissions.members_count,
           group: escapeExpression(allowedGroups[0]),
           group_2: escapeExpression(allowedGroups[1]),
-          count: allowedGroups.length,
         })
       );
     } else {
diff --git a/plugins/chat/config/locales/client.en.yml b/plugins/chat/config/locales/client.en.yml
index d18182eea7..aa66e430db 100644
--- a/plugins/chat/config/locales/client.en.yml
+++ b/plugins/chat/config/locales/client.en.yml
@@ -116,10 +116,10 @@ en:
         without_membership:
           one: "%{username} has not joined this channel."
           other: "%{username} and %{others} have not joined this channel."
-        group_mentions_disabled: 
+        group_mentions_disabled:
           one: "%{group_name} doesn't allow mentions"
           other: "%{group_name} and %{others} doesn't allow mentions"
-        too_many_members: 
+        too_many_members:
           one: "%{group_name} has too many members. No one was notified"
           other: "%{group_name} and %{others} have too many members. No one was notified"
         warning_multiple:
@@ -132,12 +132,16 @@ en:
             all: "Nobody will be notified"
           unreachable:
             one: "@%{group} doesn't allow mentions"
-            other: "@%{group} and @%{group_2} doesn't allow mentions"
-          unreachable_multiple: "@%{group} and %{count} others doesn't allow mentions"
+            other: "@%{group} and @%{group_2} don't allow mentions"
+          unreachable_multiple:
+            one: "@%{group} and %{count} other group don't allow mentions"
+            other: "@%{group} and %{count} others don't allow mentions"
           too_many_members:
             one: "Mentioning @%{group} exceeds the %{notification_limit} of %{limit}"
             other: "Mentioning both @%{group} or @%{group_2} exceeds the %{notification_limit} of %{limit}"
-          too_many_members_multiple: "These %{count} groups exceed the %{notification_limit} of %{limit}"
+          too_many_members_multiple:
+            one: "This %{count} group exceeds the %{notification_limit} of %{limit}"
+            other: "These %{count} groups exceed the %{notification_limit} of %{limit}"
           users_limit:
             one: "%{count} user"
             other: "%{count} users"
@@ -272,10 +276,15 @@ en:
       create_channel:
         auto_join_users:
           public_category_warning: "%{category} is a public category. Automatically add all recently active users to this channel?"
-          warning_groups:
-            one: Automatically add %{members_count} users from %{group}?
-            other: Automatically add %{members_count} users from %{group} and %{group_2}?
-          warning_multiple_groups: Automatically add %{members_count} users from %{group_1} and %{count} others?
+          warning_one_group:
+            one: Automatically add %{count} user from %{group}?
+            other: Automatically add %{count} users from %{group}?
+          warning_two_groups:
+            one: Automatically add %{count} user from %{group} and %{group_2}?
+            other: Automatically add %{count} users from %{group} and %{group_2}?
+          warning_multiple_groups:
+            one: Automatically add %{count} user from %{group_1} and multiple other groups?
+            other: Automatically add %{count} users from %{group_1} and multiple other groups?
         choose_category:
           label: "Choose a category"
           none: "select one..."
@@ -283,7 +292,9 @@ en:
           hint_groups:
             one: Users in %{hint} will have access to this channel per the <a href=%{link} target="_blank">security settings</a>
             other: Users in %{hint} and %{hint_2} will have access to this channel per the <a href=%{link} target="_blank">security settings</a>
-          hint_multiple_groups: Users in %{hint_1} and %{count} other groups will have access to this channel per the <a href=%{link} target="_blank">security settings</a>
+          hint_multiple_groups:
+            one: Users in %{hint_1} and %{count} other group will have access to this channel per the <a href=%{link} target="_blank">security settings</a>
+            other: Users in %{hint_1} and %{count} other groups will have access to this channel per the <a href=%{link} target="_blank">security settings</a>
         create: "Create channel"
         description: "Description (optional)"
         name: "Channel name"
@@ -338,7 +349,9 @@ en:
         saved: "Saved"
         unfollow: "Leave"
         admin_title: "Admin"
-        retention_info: "Chat history will be saved for %{days} days."
+        retention_info:
+          one: "Chat history will be saved for %{count} day."
+          other: "Chat history will be saved for %{count} days."
 
       admin:
         title: "Chat"
@@ -410,8 +423,12 @@ en:
           other: "%{commaSeparatedUsernames} and %{count} others are typing"
 
       retention_reminders:
-        public: "Channel history is retained for %{days} days."
-        dm: "Personal chat history is retained for %{days} days."
+        public:
+          one: "Channel history is retained for %{count} day."
+          other: "Channel history is retained for %{count} days."
+        dm:
+          one: "Personal chat history is retained for %{count} day."
+          other: "Personal chat history is retained for %{count} days."
 
       flags:
         off_topic: "This message is not relevant to the current discussion as defined by the channel title, and should probably be moved elsewhere."
diff --git a/plugins/chat/test/javascripts/components/chat-retention-reminder-test.js b/plugins/chat/test/javascripts/components/chat-retention-reminder-test.js
index 89620f1c93..fe11e10cb9 100644
--- a/plugins/chat/test/javascripts/components/chat-retention-reminder-test.js
+++ b/plugins/chat/test/javascripts/components/chat-retention-reminder-test.js
@@ -28,7 +28,7 @@ module(
       async test(assert) {
         assert.equal(
           query(".chat-retention-reminder-text").innerText.trim(),
-          I18n.t("chat.retention_reminders.public", { days: 100 })
+          I18n.t("chat.retention_reminders.public", { count: 100 })
         );
       },
     });
diff --git a/plugins/poll/config/locales/client.en.yml b/plugins/poll/config/locales/client.en.yml
index c7fa389041..80f11b3414 100644
--- a/plugins/poll/config/locales/client.en.yml
+++ b/plugins/poll/config/locales/client.en.yml
@@ -76,7 +76,9 @@ en:
 
       breakdown:
         title: "Poll results"
-        votes: "%{count} votes"
+        votes:
+          one: "%{count} vote"
+          other: "%{count} votes"
         breakdown: "Breakdown"
         percentage: "Percentage"
         count: "Count"
@@ -91,7 +93,9 @@ en:
         insert: Insert Poll
         help:
           options_min_count: Enter at least 1 option.
-          options_max_count: Enter at most %{count} options.
+          options_max_count:
+            one: Enter at most %{count} option.
+            other: Enter at most %{count} options.
           invalid_min_value: Minimum value must be at least 1.
           invalid_max_value: Maximum value must be at least 1, but less than or equal with the number of options.
           invalid_values: Minimum value must be smaller than the maximum value.
diff --git a/script/i18n_lint.rb b/script/i18n_lint.rb
index b00de75191..fa3e2007fb 100755
--- a/script/i18n_lint.rb
+++ b/script/i18n_lint.rb
@@ -33,11 +33,18 @@ class LocaleFileValidator
     wrong_pluralization_keys: "Pluralized strings must have only the sub-keys 'one' and 'other'.\nThe following keys have missing or additional keys:",
     invalid_one_keys: "The following keys contain the number 1 instead of the interpolation key %{count}:",
     invalid_message_format_one_key: "The following keys use 'one {1 foo}' instead of the generic 'one {# foo}':",
+    missing_pluralization: "The following keys use %{count} without pluralization.\nSplit the key into `one` and `other` or add it to the allow list in `script/i18n_lint.rb`:",
   }
 
   PLURALIZATION_KEYS = ['zero', 'one', 'two', 'few', 'many', 'other']
   ENGLISH_KEYS = ['one', 'other']
 
+  COUNT_WITHOUT_PLURALIZATION_ALLOW_LIST = [
+    "errors.messages.",
+    "activemodel.errors.messages.",
+    "activerecord.errors.messages.",
+  ]
+
   def initialize(filename)
     @filename = filename
     @errors = {}
@@ -73,7 +80,7 @@ class LocaleFileValidator
       if Hash === value
         each_translation(value, current_key, &block)
       else
-        yield(current_key, value.to_s)
+        yield(current_key, value.to_s, key)
       end
     end
   end
@@ -83,22 +90,29 @@ class LocaleFileValidator
     @errors[:invalid_relative_image_sources] = []
     @errors[:invalid_interpolation_key_format] = []
     @errors[:invalid_message_format_one_key] = []
+    @errors[:missing_pluralization] = []
 
-    each_translation(yaml) do |key, value|
+    each_translation(yaml) do |full_key, value, last_key_part|
       if value.match?(/href\s*=\s*["']\/[^\/]|\]\(\/[^\/]/i)
-        @errors[:invalid_relative_links] << key
+        @errors[:invalid_relative_links] << full_key
       end
 
       if value.match?(/src\s*=\s*["']\/[^\/]/i)
-        @errors[:invalid_relative_image_sources] << key
+        @errors[:invalid_relative_image_sources] << full_key
       end
 
-      if value.match?(/{{.+?}}/) && !key.end_with?("_MF")
-        @errors[:invalid_interpolation_key_format] << key
+      if value.match?(/{{.+?}}/) && !full_key.end_with?("_MF")
+        @errors[:invalid_interpolation_key_format] << full_key
       end
 
-      if key.end_with?("_MF") && value.match?(/one {.*?1.*?}/)
-        @errors[:invalid_message_format_one_key] << key
+      if full_key.end_with?("_MF") && value.match?(/one {.*?1.*?}/)
+        @errors[:invalid_message_format_one_key] << full_key
+      end
+
+      if value.include?("%{count}") && !ENGLISH_KEYS.include?(last_key_part) &&
+        COUNT_WITHOUT_PLURALIZATION_ALLOW_LIST.none? { |k| full_key.start_with?(k) }
+
+        @errors[:missing_pluralization] << full_key
       end
     end
   end