I am working on data where the words are in French.
I want grepl to take into account the word, whether the vowel has an accent or not.
Here is a part of code:

Here I want grepl to spot all word that are radiothérapie or radiotherapie, that is to ignore the accent

ifelse(grepl("Radiothe(é)rapie",mydata$word),"yes","no")

>Solution :

ifelse(grepl("Radioth[eé]rapie", c("Radiotherapie", "Radiothérapie", "Radio")),"yes","no")