Added lisp as a character trait (#20350)

Content.Server/Speech/EntitySystems/FrontalLispSystem.cs

@@ -0,0 +1,30 @@
+using System.Text.RegularExpressions;
+using Content.Server.Speech.Components;
+
+namespace Content.Server.Speech.EntitySystems;
+
+public sealed class FrontalLispSystem : EntitySystem
+{
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<FrontalLispComponent, AccentGetEvent>(OnAccent);
+    }
+
+    private void OnAccent(EntityUid uid, FrontalLispComponent component, AccentGetEvent args)
+    {
+        var message = args.Message;
+
+        // handles ts, c(iey), z, ps, ti
+        message = Regex.Replace(message, @"[T]+[S]+|[C]+(?=[IEY])|[Z]+|[P][S]+|[T](?=[I])", "TH");
+        message = Regex.Replace(message, @"[Tt]+[Ss]+|[Cc]+(?=[IiEeYy])|[Zz]+|[Pp][Ss]+|[Tt](?=[Ii])", "th");
+        // handles ex
+        message = Regex.Replace(message, @"(?![E])[X]", "KTH");
+        message = Regex.Replace(message, @"(?![Ee])[Xx]", "kth");
+        // handles sth and s
+        message = Regex.Replace(message, "[S]+[T]?[H]?", "TH");
+        message = Regex.Replace(message, "[Ss]+[Tt]?[Hh]?", "th");
+
+        args.Message = message;
+    }
+}