[1] Most modern continental West Germanic languages developed final devoicing, the earliest evidence appearing in Old Dutch around the 9th or 10th century.
In contrast to other continental West Germanic languages, (Eastern)-Yiddish notably does not alter final voiced sounds; this appears to be a later reversal, most probably under Slavic influence.
In its earliest recorded example (Yiddish, written evidence), it has final-obstruent devoicing (טַק "tak" instead of "tag" for day.)
Nevertheless, voiced obstruents are devoiced to some extent in final position in English, especially when phrase-final or when followed by a voiceless consonant (for example, bad cat [bæd̥ kʰæt]).
It can be inferred from the modern pronunciation of half with a voiceless /f/, from an originally voiced fricative [β] in Proto-Germanic *halbaz (preserved in German halb and Gothic halba).
Some examples from Northern German include: Final-obstruent devoicing can lead to the neutralization of phonemic contrasts in certain environments.