diff --git a/.github/workflows/translation-check.yml b/.github/workflows/translation-check.yml
index 60d8a2d40d..e3e9ccc494 100644
--- a/.github/workflows/translation-check.yml
+++ b/.github/workflows/translation-check.yml
@@ -10,6 +10,7 @@ on:
   push:
     paths:
       - 'src/translation/wininstaller/**'
+      - 'src/translation/*.ts'
       - 'tools/check-wininstaller-translations.sh'
       - '.github/workflows/translation-check.yml'
 
@@ -24,5 +25,7 @@ jobs:
         uses:        actions/checkout@v6
       - name:        "Check Windows installer translations"
         run:         ./tools/check-wininstaller-translations.sh
+      - name:        "Check application translations"
+        run:         pip install PyGithub && ./tools/check-translations.py
       #- name:       "Check for duplicate hotkeys (will not fail)"
       #  run:        sudo apt install libxml-simple-perl && cd src/translation/ && perl ./tools/checkkeys.pl
diff --git a/tools/check-translations.py b/tools/check-translations.py
new file mode 100755
index 0000000000..7d60a99fa6
--- /dev/null
+++ b/tools/check-translations.py
@@ -0,0 +1,238 @@
+#!/usr/bin/env python3
+#
+##############################################################################
+# Copyright (c) 2026
+#
+# Author(s):
+#  ChatGPT
+#  ann0see
+#  The Jamulus Development Team
+#
+##############################################################################
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+#
+##############################################################################
+
+"""
+Qt TS translation checker.
+
+This tool validates Qt `.ts` translation files according to Qt Linguist
+semantics.
+Warnings are reported with best-effort line numbers. In strict mode, the
+presence of any warning results in a non-zero exit code to allow CI failure.
+"""
+
+import argparse
+import re
+import sys
+import xml.etree.ElementTree as ET
+from collections import defaultdict
+from dataclasses import dataclass
+from enum import IntEnum
+from pathlib import Path
+
+# Regex helpers
+PLACEHOLDER_RE = re.compile(r"%\d+")
+HTML_TAG_RE = re.compile(r"<[^>]+>")
+
+# ANSI escape codes
+BOLD = "\033[1m"
+CYAN = "\033[36m"
+YELLOW = "\033[33m"
+RED = "\033[31m"
+RESET = "\033[0m"
+
+# Severity Enum
+class Severity(IntEnum):
+    WARNING = 1
+    SEVERE = 2
+
+# Data structures
+@dataclass(frozen=True)
+class MessageContext:
+    ts_file: Path
+    line: int
+    lang: str
+    source: str
+    translation: str
+    tr_type: str
+    excerpt: str
+
+@dataclass(frozen=True)
+class WarningItem:
+    ts_file: Path
+    line: int
+    message: str
+    severity: Severity
+
+# Helpers
+def approximate_message_lines(text: str):
+    """Yield approximate line numbers for <message> elements."""
+    lines = text.splitlines()
+    cursor = 0
+    for _ in range(text.count("<message")):
+        for i in range(cursor, len(lines)):
+            if "<message" in lines[i]:
+                cursor = i + 1
+                yield i + 1
+                break
+        else:
+            yield 0
+
+# Checks
+def check_language_header(ts_file: Path, root):
+    file_lang = ts_file.stem.replace("translation_", "")
+    header_lang = root.attrib.get("language", "")
+    if header_lang != file_lang:
+        return [WarningItem(ts_file, 0,
+                            f"Language header mismatch '{header_lang}' != '{file_lang}'",
+                            Severity.WARNING)]
+    return []
+
+def check_empty_translation(ctx: MessageContext):
+    if not ctx.translation and ctx.tr_type != "unfinished":
+        return [WarningItem(ctx.ts_file, ctx.line,
+                            f"{ctx.lang}: empty translation for '{ctx.excerpt}...'",
+                            Severity.SEVERE)]
+    return []
+
+def check_placeholders(ctx: MessageContext):
+    if ctx.tr_type != "unfinished" and set(PLACEHOLDER_RE.findall(ctx.source)) != set(PLACEHOLDER_RE.findall(ctx.translation)):
+        return [WarningItem(ctx.ts_file, ctx.line,
+                            f"{ctx.lang}: placeholder mismatch for '{ctx.excerpt}...'\n"
+                            f"Source: {ctx.source}\nTranslation: {ctx.translation}",
+                            Severity.WARNING)]
+    return []
+
+def check_html(ctx: MessageContext):
+    if HTML_TAG_RE.search(ctx.source) and not HTML_TAG_RE.search(ctx.translation) and ctx.tr_type != "unfinished":
+        return [WarningItem(ctx.ts_file, ctx.line,
+                            f"{ctx.lang}: HTML missing for '{ctx.excerpt}...'\n"
+                            f"Source: {ctx.source}\nTranslation: {ctx.translation}",
+                            Severity.WARNING)]
+    return []
+
+def check_whitespace(ctx: MessageContext):
+    if ctx.source != ctx.source.strip() or ctx.translation != ctx.translation.strip():
+        return [WarningItem(ctx.ts_file, ctx.line,
+                            f"{ctx.lang}: leading/trailing whitespace difference for '{ctx.excerpt}...'",
+                            Severity.WARNING)]
+    return []
+
+def check_newline_consistency(ctx: MessageContext):
+    if ctx.source.endswith("\n") != ctx.translation.endswith("\n"):
+        return [WarningItem(ctx.ts_file, ctx.line,
+                            f"{ctx.lang}: newline mismatch for '{ctx.excerpt}...'",
+                            Severity.WARNING)]
+    return []
+
+# Detect warnings
+def detect_warnings(ts_file: Path):
+    try:
+        text = ts_file.read_text(encoding="utf-8")
+        root = ET.fromstring(text)
+    except (OSError, ET.ParseError) as exc:
+        return [WarningItem(ts_file, 0,
+                            f"Error reading or parsing XML: {exc}",
+                            Severity.SEVERE)]
+
+    warnings = []
+    warnings.extend(check_language_header(ts_file, root))
+
+    file_lang = ts_file.stem.replace("translation_", "")
+    message_lines = approximate_message_lines(text)
+
+    for context in root.findall("context"):
+        for message, line in zip(context.findall("message"), message_lines):
+            source = (message.findtext("source") or "").strip()
+            tr_elem = message.find("translation")
+            translation = ""
+            tr_type = ""
+            if tr_elem is not None:
+                translation = (tr_elem.text or "").strip()
+                tr_type = tr_elem.attrib.get("type", "")
+            excerpt = source[:30].replace("\n", " ")
+
+            ctx = MessageContext(ts_file, line, file_lang, source, translation, tr_type, excerpt)
+
+            # All checks
+            warnings.extend(check_empty_translation(ctx))
+            warnings.extend(check_placeholders(ctx))
+            warnings.extend(check_html(ctx))
+            warnings.extend(check_whitespace(ctx))
+            warnings.extend(check_newline_consistency(ctx))
+
+    return warnings
+
+# CLI
+def main():
+    parser = argparse.ArgumentParser(description="Qt TS translation checker with extended rules")
+    parser.add_argument("--ts-dir", type=Path, default=Path("src/translation"),
+                        help="Directory containing translation_*.ts files")
+    parser.add_argument("--strict", action="store_true",
+                        help="Exit non-zero if any warning is found")
+    args = parser.parse_args()
+
+    if not args.ts_dir.exists():
+        print(f"Directory not found: {args.ts_dir}", file=sys.stderr)
+        return 2
+    ts_files = sorted(args.ts_dir.glob("translation_*.ts"))
+    if not ts_files:
+        print(f"No TS files found in {args.ts_dir}", file=sys.stderr)
+        return 2
+
+    all_warnings = []
+    for ts_file in ts_files:
+        all_warnings.extend(detect_warnings(ts_file))
+
+    grouped = defaultdict(list)
+    for w in all_warnings:
+        grouped[(w.ts_file, w.line)].append(w)
+
+    # Detailed output
+    for (file, line), messages in sorted(grouped.items()):
+        for w in messages:
+            color = RED if w.severity == Severity.SEVERE else YELLOW
+            print(f"{BOLD}{file}{RESET} {CYAN}line {line}{RESET}: {color}{w.message}{RESET}")
+
+    # Test summary
+    failures_by_language = defaultdict(lambda: {"severe":0, "warning":0})
+    all_languages = set()
+
+    for w in all_warnings:
+        lang = w.ts_file.stem.replace("translation_", "")
+        all_languages.add(lang)
+        if w.severity == Severity.SEVERE:
+            failures_by_language[lang]["severe"] += 1
+        else:
+            failures_by_language[lang]["warning"] += 1
+
+    print("\n== Test Summary ==")
+    for lang in sorted(all_languages):
+        counts = failures_by_language[lang]
+        print(f"{BOLD}[{lang}]{RESET} Severe: {counts['severe']}, Warnings: {counts['warning']}")
+
+    total_severe = sum(f["severe"] for f in failures_by_language.values())
+    total_warning = sum(f["warning"] for f in failures_by_language.values())
+    print(f"\nTotal Severe: {total_severe}, Total Warnings: {total_warning}")
+
+    if total_severe > 0 or (args.strict and total_warning > 0):
+        return 1
+
+    return 0
+
+if __name__ == "__main__":
+    sys.exit(main())