What is the meaning of -cha?

Alternative form of ya (you)

attached to truncated stems of common nouns to form feminine or masculine nouns, often augmentative or derogatory

attached to truncated stems of given names to form nicknames

Factive suffix. Verbalizes nouns (N→V). Expresses that the head noun is being made, built, shaped, turned into, added or removed from something else.

Diminutive suffix (N→N). Used to indicate a smaller size or to convey affection.

suffix to form adverbs when added to names of ethnic groups or countries

names the languages of these groups or countries

allomorph of -ta used for stems that end in i

Source: wiktionary.org