My partner, Myriam, a 47 year old married woman who lives with her husband and son works as a assistant teacher and speak Spanish and Chinese, the language of the country, pure, which is on of the continent of America, and of his hometown, Lima, which has a population of two million, She has been in New York for 18 years and feels happy here.



This is fine.  Errors are few.

1. In the third person singular ("he, she it") present tense, there has to be an "s' at the end of verbs. I think you know that. You put the "s" after all the verbs except one. You can find it.

2. Check spelling. The name of the country is Peru."

3. The article "a" comes before words that begin with a consonant ("b, c, d, f, g, h (with exceptions, like "hour," when "h" isn't pronounced as a consonant), j, k, l, m, n, p, r, s, t, v, w, y, z), but the correct article is "an" before vowels (a, i, e, o, u). so  the correct phrase is "an assistant teacher."

4. You mistook "her" for "his" once.

5. You should have used only one (not two) prepositions: "..which is on the continent of.." is correct.

6. There should be a period (.) not a comma (," at the end of a sentence. "....two million. She has been.." is correct.