Cumbraek makes occasional use of three diacritics:
- The acute accent (´) is used to mark a long vowel. Where it occurs in the final syllable, it also marks stress (e.g. cantín ‘canteen’, cróssan ‘fool’).
- The grave accent (`) is used to mark a stressed vowel (e.g. russèt ‘recipe’). In monosyllables it is used to show a short vowel (e.g. bùs ‘bus’)
- The trema (¨) is placed on the second in a series of vowels to mark diaeresis (e.g. troäv ‘I turn’)
Punctuation should generally follow the English model but a number of punctuation marks have specific uses in Cumbraek:
- hyphens (-) are used to join elements of a compound word, in which the first word is inflected (e.g. askurn-cevin ‘backbone’, pl. eskirn-cevin). They are also used to join auxiliary pronouns to nouns or verbs (e.g. can-ev ‘he sings’, i livir-hi ‘her book’)
- apostrophes (‘) show omission of a letter (e.g. a’r ti ‘and the house’). They are also used with the infixed pronouns (e.g. a’m tat ‘and my father’) and in a number of compound prepositions/adverbs where the stress is on the nominal element (e.g. war’lorr ‘behind’).