linguistic and non linguistic factors of English would be the same as verbal and non-verbal factors.

verbal/linguistic: what you say and how you say it (words, tone of voice)

non-verbal/non linguistic: gesture, body position, facial expression

"Linguistic" is a word that means pertaining to words or language.

using picture instead of words

Semantics is the study of the meaning of words, so a semanticist a person who is a specialist in the study of linguistic meaning.