Cite this: eDIL s.v. B or dil.ie/5052

Forms: beithe

second letter in the Irish alphabet, and the first consonant of the Ogam alphabet. Irish name beithe birch ; hence beithe luis, name of Ogam alphabet, see IGT Introd. § 4.

O.Ir. b in absolute initial position, after m (imb), and sometimes after l (Albu) and r (orbae) represents the voiced labial plosive (Mod. Ir. b), and derives from IE *b, *bh and *gw ( GOI § 188 ). In other positions it represents the voiced labial fricative (Mod. Ir. bh), and derives (i) from the sources already mentioned, together with *p in IE *-pr-, *-pl- (accabor, díabul), ib. § 227 , and (ii) from IE *u in certain positions (tarb, cubus, etc.). It is possible, however, that the sound in case (ii) was not phonetically identical with that in case (i), since they sometimes have different sandhi treatment; compare dupall (dub-ball) with atrefea (atreb-fea) and derbráthair, modern dearbhráthair (derbbráthair); compare also ropia (ro-b-bia), and in later gairpeann (from garbh + peann), IGT Introd. § 42. The -b(-) of the O.Ir. f-future is, according to the latest explanation of this formation (Watkins, Ériu xx), a voicing of f < *sw.

O.Ir. bb in all positions represents the unlenited sound (abb, abbán).

In Latin loanwords initial b- remains (baithis, baitsid). Ir. b- sometimes represents Lat. p- ( bóc, Sg. 46a2 ), and medial -b- (<earlier -p-), representing a voiced plosive, Lat. -p- (puball s.v. pupall, abstal, Wb. 10c16 ). The Lat. post-vocalic voiced stop -b- became in Irish a voiced fricative (scríb(a)id, Mod. Ir. scríobhaidh). For -b- for Lat. -f- (cobais) see GOI § 201.

In the later language b combines with prec. m (Mid.Ir. imm for imb), and initial mr, ml, become br-, bl- (brath, bláith for older mrath, mláith); medial lenited b and m are sometimes confused (mebuir for memuir).