Translate a Flutter app into German

What German changes in a Flutter UI

German text is often 20 to 35% longer than English, and a short label can double in width. In Flutter this shows up quickly: a Row that fitted in English throws the yellow-and-black stripes and a RenderFlex overflowed error in German.

• Compound nouns: “Notification settings” becomes Benachrichtigungseinstellungen, one word with no space. It will not break at a sensible syllable on its own, so plan for Flexible, maxLines and TextOverflow.ellipsis where space is tight.
• Capitalised nouns: every noun takes a capital (Konto, Passwort, Warenkorb). A lower-case German label looks like a mistake.
• Sie or du: formal Sie (“Geben Sie Ihr Passwort ein”) is standard in business software; many consumer apps use informal du (“Gib dein Passwort ein”). Decide before translating and keep it consistent.
• Buttons: German UIs typically use the infinitive (Speichern, Abbrechen, Weiter), which keeps buttons short.

Plurals, placeholders and formats: German-specific traps

German has only two CLDR plural categories, one and other, much like English, so zero takes the plural: 0 Nachrichten. If your source is French, note that French treats 0 as singular, which German does not. A sound ICU message looks like this:

{count, plural, =0{Keine Nachrichten} =1{1 Nachricht} other{{count} Nachrichten}}

select messages need care too: German inflects articles and adjectives by gender and case, so sentences built by concatenation (“Welcome, ” + name + “!”) translate badly. Use a full string with a placeholder instead: "welcome": "Willkommen, {name}".

Do not hard-code dates or numbers in values. German writes 31.12.2025 and uses a decimal comma (1.234,56); a placeholder typed as DateTime or double, with its format declared in the @ metadata, lets the intl package render the right form for the de locale.

What Manuce returns, and what it does not do

You get back the same file in the same format: indentation, key order, quotes, comments, line endings, encoding and BOM are preserved; only the values change, and @@locale becomes de.

• @ keys are not translated; their description fields are used as context. Writing “button, max 12 characters” in a description helps get Weiter rather than a long phrase.
• {name} placeholders and ICU plural and select messages are checked, and German plural categories are added.
• Each translated value is compared with the source (variables, tags); if a mismatch persists, the source value is kept and the report says so.
• Left as they are: keys, empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything marked as non-translatable.

Manuce does not edit your Dart code, does not test layouts and cannot see strings hard-coded outside your .arb files. Nor does it provide certified (sworn) translation, should your terms of use ever require one. Pricing covers only the words in values, keys and tags excluded, and German is charged at the base rate.

Preparing your .arb files

• Send an up-to-date template file (for example app_en.arb): every visible string must be in it, as text left in Text('…') widgets will not be translated.
• Fill in description for ambiguous strings: “Archive” may be a button verb (Archivieren) or a tab name (Archiv).
• State whether the app uses Sie or du, and which brand names stay untranslated.
• Replace concatenations with placeholder strings, and “1 item(s)” patterns with a proper plural message.

Checking the German build

1. Put the returned file in your localisation folder, add Locale('de') to supportedLocales if needed, and run flutter gen-l10n.
2. Read the report: a string left in the source language often points to a malformed placeholder in the original.
3. Switch the device to German and go through narrow screens: tab bars, buttons, AppBar titles, dialogs. Test with a larger system font size as well, which makes overflow worse.
4. For iOS, check that German is declared in CFBundleLocalizations in Info.plist, otherwise the language may not be offered.
5. Check plurals with 0, 1 and 2 items, and how dates display.

In practice

1. Export your up-to-date template .arb file, with descriptions on ambiguous strings.
2. Upload it to Manuce, choose German and a level, and review the free sample.
3. Download the translated file and the report of strings left unchanged.
4. Drop the file into your project, run flutter gen-l10n and test narrow screens in German.