Deaf Irish men and women who went to school in the mid 20th century would have learned different sign languages.
"The fact that the Catholic schools are segregated on the basis of gender led to the development of a gendered-generational variant of Irish Sign Language that is still evident (albeit to a lesser degree) today."
It's very typical for Signed Languages to have multiple centers usually the schools for Deaf. Swiss German Sign Language for example has five centers for Bern, Basel, Zürich, Luzern and St. Gallen. People say today that Swiss German Sign Language has five dialects and this usually wows people, even the Alemannic Swiss who themselves have many variants in their Alemannic dialect.
Ireland is special that they gender-segretated the Deaf children and the consequence is that women and men have different dialects.
"The fact that the Catholic schools are segregated on the basis of gender led to the development of a gendered-generational variant of Irish Sign Language that is still evident (albeit to a lesser degree) today."
https://en.wikipedia.org/wiki/Irish_Sign_Language