diff --git a/codacy-plugins-api/src/main/scala/com/codacy/plugins/api/languages/Language.scala b/codacy-plugins-api/src/main/scala/com/codacy/plugins/api/languages/Language.scala
index 75c29b9..97b380c 100644
--- a/codacy-plugins-api/src/main/scala/com/codacy/plugins/api/languages/Language.scala
+++ b/codacy-plugins-api/src/main/scala/com/codacy/plugins/api/languages/Language.scala
@@ -256,33 +256,37 @@ object Languages {
 
   case object Haskell extends Language(extensions = Set(".hs", ".lhs"))
 
-  case object Erlang extends Language(extensions = Set(".erl"))
+  case object Erlang
+      extends Language(extensions = Set(".erl", ".hrl", ".es", ".escript"), files = Set("rebar.config", "rebar.lock"))
 
-  case object Elm extends Language(extensions = Set(".elm"))
+  case object Elm extends Language(extensions = Set(".elm"), files = Set("elm.json", "elm-package.json"))
 
-  case object HTML extends Language(extensions = Set(".html"))
+  case object HTML extends Language(extensions = Set(".html", ".htm", ".xhtml"))
 
   // Others
 
-  case object Perl extends Language(extensions = Set(".pl"))
+  case object Perl
+      extends Language(extensions = Set(".pl", ".pm", ".pod", ".perl", ".t"),
+                       files = Set("cpanfile", "cpanfile.snapshot"))
 
-  case object FSharp extends Language(extensions = Set(".fs"))
+  case object FSharp extends Language(extensions = Set(".fs", ".fsi", ".fsx"), files = Set("paket.lock"))
 
-  case object Fortran extends Language(extensions = Set(".f90", ".f95", ".f03"))
+  case object Fortran extends Language(extensions = Set(".f90", ".f95", ".f03", ".f", ".for", ".f77", ".f08"))
 
-  case object R extends Language(extensions = Set(".r"))
+  case object R extends Language(extensions = Set(".r", ".rd", ".rsx"), files = Set("renv.lock", ".Rprofile"))
 
-  case object Scratch extends Language(extensions = Set(".scratch", ".sb", ".sprite", ".sb2", ".sprite2"))
+  case object Scratch
+      extends Language(extensions = Set(".scratch", ".sb", ".sprite", ".sb2", ".sprite2", ".sb3", ".sprite3"))
 
-  case object Lua extends Language(extensions = Set(".lua"))
+  case object Lua extends Language(extensions = Set(".lua", ".luau"))
 
-  case object Lisp extends Language(extensions = Set(".asd", ".el", ".lsp", ".lisp"))
+  case object Lisp extends Language(extensions = Set(".asd", ".el", ".lsp", ".lisp", ".cl"))
 
-  case object Prolog extends Language(extensions = Set(".P", ".swipl"))
+  case object Prolog extends Language(extensions = Set(".P", ".swipl", ".pro", ".prolog"))
 
-  case object Julia extends Language(extensions = Set(".jl"), files = Set("Manifest.toml"))
+  case object Julia extends Language(extensions = Set(".jl"), files = Set("Manifest.toml", "Project.toml"))
 
-  case object OCaml extends Language(extensions = Set(".ml", ".mli", ".mly", ".mll"))
+  case object OCaml extends Language(extensions = Set(".ml", ".mli", ".mly", ".mll"), files = Set("dune-project"))
 
   case object Solidity extends Language(extensions = Set(".sol"))
 
diff --git a/codacy-plugins-api/src/test/scala/com.codacy.plugins.api.languages/LanguageSpec.scala b/codacy-plugins-api/src/test/scala/com.codacy.plugins.api.languages/LanguageSpec.scala
index e16a779..32c4efb 100644
--- a/codacy-plugins-api/src/test/scala/com.codacy.plugins.api.languages/LanguageSpec.scala
+++ b/codacy-plugins-api/src/test/scala/com.codacy.plugins.api.languages/LanguageSpec.scala
@@ -32,5 +32,58 @@ class LanguageSpec extends AnyWordSpec with Matchers with OptionValues {
         .value shouldBe Languages.Scala
       Languages.forPath("src/File3.mjs").value shouldBe Languages.Javascript
     }
+
+    "forPath resolves extensions case-insensitively" in {
+      // extensions are stored lowercase; lookup lowercases the file's extension too
+      Languages.forPath("src/analysis.R").value shouldBe Languages.R
+      Languages.forPath("man/topic.Rd").value shouldBe Languages.R
+      Languages.forPath("src/Main.FS").value shouldBe Languages.FSharp
+    }
+
+    "forPath resolves newly added extensions" in {
+      val cases = Seq("mod.hrl" -> Languages.Erlang,
+                      "script.es" -> Languages.Erlang,
+                      "cli.escript" -> Languages.Erlang,
+                      "legacy.f" -> Languages.Fortran,
+                      "legacy.for" -> Languages.Fortran,
+                      "legacy.f77" -> Languages.Fortran,
+                      "modern.f08" -> Languages.Fortran,
+                      "sig.fsi" -> Languages.FSharp,
+                      "script.fsx" -> Languages.FSharp,
+                      "lib.pm" -> Languages.Perl,
+                      "docs.pod" -> Languages.Perl,
+                      "script.perl" -> Languages.Perl,
+                      "some.t" -> Languages.Perl,
+                      "man.rd" -> Languages.R,
+                      "sweave.rsx" -> Languages.R,
+                      "page.htm" -> Languages.HTML,
+                      "page.xhtml" -> Languages.HTML,
+                      "rules.pro" -> Languages.Prolog,
+                      "rules.prolog" -> Languages.Prolog,
+                      "core.cl" -> Languages.Lisp,
+                      "project.sb3" -> Languages.Scratch,
+                      "sprite.sprite3" -> Languages.Scratch,
+                      "config.luau" -> Languages.Lua)
+      cases.foreach {
+        case (path, language) => Languages.forPath(path).value shouldBe language
+      }
+    }
+
+    "forPath resolves newly added manifest and lock files" in {
+      val cases = Seq("rebar.config" -> Languages.Erlang,
+                      "rebar.lock" -> Languages.Erlang,
+                      "elm.json" -> Languages.Elm,
+                      "elm-package.json" -> Languages.Elm,
+                      "paket.lock" -> Languages.FSharp,
+                      "cpanfile" -> Languages.Perl,
+                      "cpanfile.snapshot" -> Languages.Perl,
+                      "renv.lock" -> Languages.R,
+                      ".Rprofile" -> Languages.R,
+                      "Project.toml" -> Languages.Julia,
+                      "dune-project" -> Languages.OCaml)
+      cases.foreach {
+        case (path, language) => Languages.forPath(path).value shouldBe language
+      }
+    }
   }
 }