The example of Gaelic here in Ireland is a poor one. The attempt to preserve the language has been badly handled. It is compulsory for every child to learn Gaelic through first and second level education, and never spoken afterwards (except for one or two areas totaling less than 1% of the population).
Many people end up resenting Gaelic after being forced to learn it for no practical purpose. This is a shame because it is a beautiful language to read and speak.