unolingual 

Spanglish; a person that speaks only English and does not plan to learn or even try to learn Spanish

In an annoyed tone, she replied to her colleague who always greeted her in Spanish "I don't speak Spanish, I am unolingual"

unolingual by tofallinlovewith October 4, 2013

Unilingual

The opposite of bilingual. If you only speak one language, you're unilingual.

40% of the people in the world are unilingual.

Unilingual by Lumby_Jack July 11, 2017

Nolingual 

Refers to a person speaking no languages fluently. It can sometimes be referred as multilingual depending on the user.

A famous artist, Park Jaehyung of the Korean band Day6, is nolingual.

"Feel more nolingual these days"

Nolingual by standay6 September 18, 2019