פֿאָטער
דער
'father'

ETYMOLOGY

[DW¹ notes that many German dialects preserved the short -a- - not in Yiddish (except in westernmost Western Yiddish?).
Interesting that Yiddish does not preserve the umlaut in the plural, which arose in MHG and came to dominate in NHG. Maybe this indicates that the word was not used much, or in order to maintain a distinction from פֿעטער 'uncle', which would sound the same in Northeastern Yiddish.]
Got. fadar, ON faðir, OE fæder, English father, OS fadar, Dutch vader, OHG fatar, MHG vater, NHG Vater; from PGmc ✱fader-; from PIE ✱ph₂-tér- (or ✱pətḗr); a hysterokinetic ter-stem: ✱ph₂-tér, (gen.) ✱ph₂-tr-ós, (acc.) ✱ph₂-tér-m. The word referred to the public role of the father as head of the household; another more familiar term was also used in many language (see טאַטע).
Related: Sanskrit pitā́, pitár- Greek πᾰτήρ, (gen.) πᾰτρός, Latin pater, patris,
{Burrow 103; DW¹ 25: 13; Kluge/Seebold 2011: 948; Kroonen 2013: 121}
Vowel 13 (or A3 - MHG short a lengthened in an open syllable), Proto-Yiddish ✱a

NEY /fot3r/
CY /fu:t3r/

WESTERN

Old Literary Yiddish (ca. 1100-1800)

איז דר פֿאטר ברוגז איבר דען בחור גיוועזן
'the father was angry about the young man'

Switzerland

(pl.) unseri fɛterə {SWITZERLAND, Fleischer 2005}

vatter {EAST FRIESLAND, Aurich, Schulenrufen 1902}

Oyberland (West Transcarpathian)

yn doːz zɛnən də feːtα און דאָס זענען די פֿעטער {WTCP, Dunajská Streda, 47179}

deˑs zən də ziˑn yn deˑs zɛn də feˑtər, taˑtəs דאָס זענען די זין און דאָס זענען די פֿעטער, טאַטעס {WTCP, Vác, 47197}

CENTRAL

fūətər {eastern SLOVAKIA and CARPATHO-RUTHENIA, Beranek 1936: 72}

Unterland (East Transcarpathian)

fūətər 'Vater' {ETCP, Beranek 1941}

iˑnəns futər אינענס פֿאָטער 'your father' (polite) {ETCP, Sîg Felső Szek, 47223}
- dɩ fejtər די פֿעטער

פֿאָטער דײַטש {POLAND, Wolbrom, 50196}

fuˑtəs פֿאָטערס {POLAND, Warsaw, 52211}