Here is a new prespective for you; Oghum is a Turkish word meaning I am OK.Old Turks were known as The Ons and the OKs.The word Gael comes from the word OG-A-EL which means a people who reached GOD. The Celts came from Central Asia and spoke a different form of Proto-Turkish
Thousands years ago when the Central Asia Steppes turned into deserts and the streams and greenary dried up people of Great Steppe’s had to leave their homeland and migrated to Northern Europe which was melting slowly after the last Ice Age and for those people it was unshared-inhabited land. They brought their culture and language. That is why The Celtic culture is a nice reflection of Turkic culture.
Even there is a silent G in Turkish and as there was no silent G in English, Old Irish language added a H after G to produce the same sound as in ArdaGH, and any word ending with GH. By the way DAGH means mountain in Turkish.
Even the old Irish ballads, melodically and by the view point of scale, it sounds like Old Turkish ballads.Old Turkish music is based on a whistle which was used by the shepherds on the mountains and it sounded exactly the same way the Irish whistle. There are at least 5000 km between Ireland and Turkey/Middle Asia??? Irish scholars must investigate / research old Turkish language to track and trace the first Irish/Celts.
For reference: http://www.adji.ru

Regards, Korkut