Although the concept of Valentine’s Day doesn’t really exist in Gàidhlig, you can still wish loved ones a happy day using the following approximation:

@GaelicLessons Bhàlantain without the ‘e’ and pron. /VAlantain/

— Àdhamh Ó Broin (@An_Comhghallach) February 14, 2014

Thanks to @GaelicLessons and @An_Comhghallach