моя російська і українська змішані.

:)

Language - мова - is a feminine noun, that's why we use моя, російська, українська.

-а and -я are always the endings for feminine adjectives and possesive pronouns.

Note also that in Ukrainian the verb to be - є - is almost always omitted.

My Russian and Ukrainian are mixed.

мій моя російськийа і українськийа є змішаними (the word "language (мова)" has a female gender in Ukrainian.