These days, modern English speakers tend to use the word bray to exclusively refer to the sound that a donkey or mule makes, e.g. “the mule in the field is braying”.
Here is an audio clip of a braying mule: https://www.youtube.com/watch?v=kzm4z-Rg1sQ.
Modern English speakers do not tend to go to the zoo with their friends or family and say “look at those monkeys/elephants/sparrows/hens/sheep braying”. However, it would appear that the closely equivalent Anglo Norman verb braire, derived from the Old French word brai or brait, meaning ‘cry’, could be applied to the sounds made by a number of things: humans, animals of various kinds, even water. As can be seen from the citations below (which are all taken from the Anglo Norman Dictionary entry for braire: http://www.anglo-norman.net/D/braire), it could be used to refer to:
A general roar or howl:
To roar, howl: rudere: brayer TLL ii 12; vagit: brayet TLL i 147; pandatio -as .i. braeer Gloss Bod 730 202.27;
Humans shouting, or wailing:
(Of the noise made by humans) to shout, yell: Qui donc fu pres d’iluec grant noise put oir, Braire les chevalers e les chevals henir Rom Chev ANTS 3522; jeo criay ebrayay YBB 33-35 Ed I 123; ♦ to cry, wail: Les enfaunz […] En cryaunt braerent pyteusement S Fran ANTS 6868; or … ♦ to wail, lament: Iluec les (=the damned in Hell) oi saint Paul estrange doel faire, E crier e braere cum se ço fust toneire Descent 159-60; Sainte Eglise crie e brait Pur cels qui li malfé deceit Mirur 87ra16;
(Of the noise made by various animals) to roar: il cria cume leun quant ilbreit Apoc 1814; urse brait (M.E. braies) BIBB (O) 333va;
(Of monkeys) to cry: Senge braie (M.E. Ape scrikith) Nom 744;
(Of sheep) to bleat: Kaunt ele targast au lever Matyn le ayngnel soleyt braer S Fran ANTS 3672;
(Of hens) to cackle: la geline quant ele ad pont ne fest forsbrere Ancren2 180.9;
(Of sparrows) to twitter: moisson favele toz jours e bret e jangle e crie Ancren2 237.34;
(Of elephants) to trumpet: barrit: noys, criet, brayet TLL i 338; 3 (of water) to roar: la mer […] Undeie e brait cum esragee S Gile 782; toutes estes en cest corant, en la braanteeve del siecle qe nuiz porte avalante Ancren1 51.11; Cist mundes est ausi cum mer Ke ja ne set en pais ester, Mais tutdis bruit et tutdis brait Corset ANTS 1501;
Rushing or roaring water:
(Of water) rushing, roaring: Es granz undes broiant Horn 4962; De refreider son cors il out talant D’ewe de puis u de fontainnebroiant Anc Test (B)
From a linguistic point of view, the multi-purpose nature of the Anglo Norman word braire tells us several interesting things. Firstly, and most obviously, it tells us that Anglo Norman braire (originally derived from the Old French word brai which would have been used in Continental France) was used in a very general way in Anglo Norman, and could be used in relation to both living creatures and features of the natural environment such as river water.
Secondly, it potentially tells us something about the relationship between Anglo Norman and Middle English within England during the medieval period. Braire is cited in Anglo Norman documents dating from as early as the 12th Century (1100 – 1200). Meanwhile, according to the OED, the first attestation of the verbal meaning of the word bray, meaning ‘To cry out, to utter a loud harsh cry; esp. of grief or pain’ within English can be found in the Cursor Mundi (a1300):
‘He sal here it [heaven] cri to wonder, bath cri and brai for dute and drede’.
(cited from the OED online: cf. http://www.oed.com/view/Entry/22839?rskey=U3Ith9&result=4&isAdvanced=false#eid).
The documentary evidence suggests that braire was being used in Anglo Norman either before, or at the same time as, it was being used in Middle English. It could therefore potentially have come into the English language through contact with Anglo Norman. In other words, English speakers may have borrowed this word from Anglo Norman, and this is how it came to be part of the English language. Examples such as this may be able to tell us something about the bilingual situation in medieval England.
Thirdly, it is worth highlighting the diachronic aspect, i.e. how the usage of this word has changed over time. The main thing to note here is that the meaning of bray has become very specialized in modern English. At some point, it began to be used within English to exclusively refer to the sound made by donkeys or mules. And what a glorious sound that is!
Note: all citations have been taken from the Anglo Norman Dictionary online: http://www.anglo-norman.net and the OED online: http://www.oed.com/. If you are interested in finding out more about the word briare, see the Anglo Norman Dictionary entry: http://www.anglo-norman.net/D/braire. The Anglo Norman Dictionary also has a blog devoted exclusively to Anglo Norman words, which can be found at this link: http://anglonormandictionary.blogspot.co.uk/.