Ifelse in R with multiple categorical conditions

this is my first time in stackoverflow, I'm sorry if this sounds simple.

I have a data set, dt.train2 with 1500 different observations and 130 variables. One of them is "languages" and it can be english, french, arabic...

I want to create a ifelse string that gives attributes 1 for english, 2 for french, 3 for spanish and 0 for anything else. I have no idea how to do it.

dt.train2[, language_string := ifelse(language == "english", 1, ifelse(language == "french", 2, ifelse(language == "spanish",3)]

I'm using this to run linear model about sales.

Thanks!!