Words for to call in Celtic languages.

Proto-Celtic	*garyo- = to cry, shout
Old Irish (Goídelc)	gairid [ˈɡarʲiðʲ] = to call, cry out, summon, name
Irish (Gaeilge)	gair [ɡaɾʲ] = to call, summon, invoke, name, proclaim, inaugurate, acclaim
Scottish Gaelic (Gàidhlig)	gàir [gaːrʲ] = to laugh, shout, cry, make a noise, resound
Manx (Gaelg)	guee = to invoke, crave, beseech, entreat, appeal, swear by, pray, beg, swear, curse
Middle Welsh (Kymraec)	garddu = word
Welsh (Cymraeg)	gair [ɡai̯r] = word; speech, phrase; greeting, salutation; short extempore address or exhortation; saying, proverb
Cornish (Kernewek)	ger = word
Old Breton	gerent = word
Breton (Brezhoneg)	ger [ˈde.bʁɪ̃] = word, phrase, question

Etymology: from the Proto-Indo-European *ǵeh₂r- (to call, cry out) [Source].

Proto-Brythonic	*gėlwɨd = to call
Welsh (Cymraeg)	galw [ˈɡalu / ˈɡaːlu] = to call, shout, bawl, summon, invite
Cornish (Kernewek)	gelwel = to call, appeal, invite, summon
Breton (Brezhoneg)	galven [ˈde.bʁɪ̃] = to call, summon

Etymology: from the Proto-Indo-European *gal(o)s- (voice, cry) [Source].

Words marked with a * are reconstructions.

Sources: Wiktionary, Am Faclair Beag, MacBain’s Dictionary, In Dúil Bélrai English – Old-Irish Glossary, teanglann.ie, On-Line Manx Dictionary, Geiriadur Prifysgol Cymru, Gerlyver Kernewek, Dictionnaire Favereau