An Coimisinéir Teanga has said there is an onus on local authorities to adhere to laws aimed at protecting the language in Gaeltacht areas.
The Irish Language Commissioner's annual report shows a total of 704 complaints were made to his office last year - an 11% increase on the 2018 figure.
Almost a fifth of complaints were made by Gaeltacht residents, with a further 35% coming from Dublin.
The report details the manner in which these complaints were addressed and outlines the findings in relation to a number of investigations carried out.
In one instance, Rónán Ó Domhnaill found that Kerry County Council breached planning laws by not implementing a language condition for a housing development in the West Kerry Gaeltacht.
The investigation was prompted by the council not including a condition on the use of Irish to the planning permission, for a development in Baile an Fheirtéaraigh.
Mr Ó Domhnaill said it was important that local authorities played a part in addressing "a language crisis" in the Gaeltacht by implementing regulations designed to promote the use of Irish.
The majority of complaints in 2019 related to signage and stationery, replies in English to correspondence in Irish, and difficulties using names and surnames in Irish.
Mr Ó Domhnaill also provides an update on how RTÉ has responded to findings that the organisation breached the broadcasting law regarding its Irish language obligations.
He says it has committed to increasing the amount of programming in Irish this year, but he is seeking more clarity on RTÉ's plans.