|Era||Approached Modern Welsh by about the 15th century|
Middle Welsh (Welsh: Cymraeg Canol, Middle English: Walsch) is the label attached to the Welsh language of the 12th to 15th centuries, of which much more remains than for any earlier period. This form of Welsh developed directly from Old Welsh (Welsh: Hen Gymraeg). The name of the language in Middle Welsh was Cymraec Canawl which had alternate spellings using ⟨k⟩ for ⟨c⟩.
Middle Welsh is the language of nearly all surviving early manuscripts of the Mabinogion, although the tales themselves are certainly much older. It is also the language of most of the manuscripts of Welsh law. Middle Welsh is reasonably intelligible, albeit with some work, to a modern-day Welsh speaker.
The phonology of Middle Welsh is quite similar to that of modern Welsh, with only a few differences. The letter u, which today represents /?/ in North Western Welsh dialects and /i/ in South Welsh and North East Welsh dialects, represented the close central rounded vowel /?/ in Middle Welsh. The diphthong aw is found in unstressed final syllables in Middle Welsh, while in Modern Welsh it has become o (e.g. Middle Welsh marchawc = Modern Welsh marchog "horseman"). Similarly, the Middle Welsh diphthongs ei and eu have become ai and au in final syllables, e. g. Middle Welsh seith = modern saith "seven", Middle Welsh heul = modern haul "sun".
The orthography of Middle Welsh was not standardised, and there is great variation between manuscripts in how certain sounds are spelled. Some generalisations of differences between Middle Welsh spelling and Modern Welsh spelling can be made. For example, the possessive adjectives ei "his, her", eu "their" and the preposition i "to" are very commonly spelled y in Middle Welsh, and are thus spelt the same as the definite article y and the indirect relative particle y. A phrase such as y gath is therefore ambiguous in Middle Welsh between the meaning "the cat" (spelt the same in Modern Welsh), the meaning "his cat" (modern ei gath), and the meaning "to a cat" (modern i gath). The voiced stop consonants /d ?/ are represented by the letters t c at the end of a word, e.g. diffryt "protection" (modern diffryd), redec "running" (modern rhedeg). The sound /k/ is very often spelled k before the vowels e i y (in Modern Welsh, it is always spelt c, e.g. Middle Welsh keivyn = modern ceifn "third cousin"). The sound /v/ is usually spelt u or v (these are interchangeable as in Latin MSS), except at the end of a word, where it is spelt f (in Modern Welsh, it is always spelt f, e.g. Middle Welsh auall = modern afall "apple tree"). The sound /ð/ is usually spelt d (in Modern Welsh, it is spelt dd, e.g. Middle Welsh dyd = modern dydd "day"). The sound /r?/ is spelt r and is thus not distinguished from /r/ (in Modern Welsh, they are distinguished as rh and r respectively, e.g. Middle Welsh redec "running" vs. modern rhedeg).
|caru, "to love"||bot, "to be"|
|He, she, it||car||yw, ys, yssyd|
Middle Welsh is closer to the other medieval Celtic languages, e.g. Old Irish, in its morphology. For example, the endings -w?s, -ws, -es and -as are used for 3rd person singular of the preterite in Middle Welsh as well as the form -odd. In the same person and tense exists the old reduplicated preterite kigleu 'he heard' of the verb klywet 'to hear', which corresponds to the Old Irish ·cúalae '(s)he heard' from the verb ro·cluinethar '(s)he hears'.
Middle Welsh also retains more plural forms of adjectives that do not appear in modern Welsh, e.g. cochion, plural of coch 'red'.
The nominal plural ending -awr is very common in Middle Welsh, but has been replaced in modern Welsh by -au.
As in modern written Welsh, the VSO word order (Gwelodd y brenin gastell: "Saw the king a castle") is not used exclusively in Middle Welsh, but irregular and mixed orders are also used: Y brenin a welodd gastell: ("[It was] the king that saw a castle"). The suggestion is that the mixed order places emphasis on the subject, and is often used in Welsh today to emphasise something. The difference between the two is that a negative particle (ni/na) precedes the subject in the mixed order (thus Ni brenin a welodd gastell would mean "It was not the king that saw the castle", but precedes the verb in the irregular order (thus Brenin ni welodd gastell = "The king did not see a castle").