invoiceninja/app/lang/de/fields.php

<?php 

return array(

  // client
  'organization' => 'Organisation',
  'name' => 'Name',
  'website' => 'Webseite',
  'work_phone' => 'Telefon',
  'address' => 'Adresse',
  'address1' => 'Straße',
  'address2' => 'Adresszusatz',
  'city' => 'Stadt',
  'state' => 'Bundesland',
  'postal_code' => 'Postleitzahl',
  'country_id' => 'Land',
  'contacts' => 'Kontakte',
  'first_name' => 'Vorname',
  'last_name' => 'Nachname',
  'phone' => 'Telefon',
  'email' => 'Email',
  'additional_info' => 'Zusätzliche Info',
  'payment_terms' => 'Zahlungsbedingungen',
  'currency_id' => 'Währung',
  'size_id' => 'Größe',
  'industry_id' => 'Kategorie',
  'private_notes' => 'Notizen',

  // invoice
  'invoice' => 'Rechnung',
  'client' => 'Kunde',
  'invoice_date' => 'Rechnungsdatum',
  'due_date' => 'Fällig am',
  'invoice_number' => 'Rechungsnummer',
  'invoice_number_short' => 'Rechnung #',
  'po_number' => 'Bestell Nummer',
  'po_number_short' => 'BN #',
  'frequency_id' => 'Wie oft',
  'dicount' => 'Rabatt',
  'taxes' => 'Steuern',
  'tax' => 'Steuer',
  'item' => 'Artikel',
  'description' => 'Beschreibung',
  'unit_cost' => 'Kosten pro Einheit',
  'quantity' => 'Menge',
  'line_total' => 'Summe',
  'subtotal' => 'Zwischensumme',
  'paid_to_date' => 'Zahlungsdatum',
  'balance_due' => 'Rechnungsbetrag',
  'invoice_design_id' => 'Design',
  'terms' => 'Bedingungen',
  'your_invoice' => 'Ihre Rechnung',
  
);