Some English language terms have letters with diacritical marks. Most of the words are loanwords from French, with others coming from Spanish, German, or other languages. Some are however originally English, or at least their diacritics are. Proper nouns are not generally counted as English terms except when accepted into the language as an eponym – such as Geiger–Müller tube, or the English terms roentgen after Wilhelm Röntgen, and biro after László Bíró, in which case any diacritical mark is often lost.