It's more like the romantic languages - French, Italian, Spanish etc all share the common root of Latin but are separate languages. An Irish speaker would not be able to understand Scottish Gaelic without learning the language.
In Scottish Gaelic you'd say "Halò" and in Scots you'd say "Hullo".
F.Knight: Chef isn't here at this moment,he goes back into his Hometown to celebrating the Halloween with them. F.Fighter: That too bad. I can't taste his dish until 3-5 days. F.Mage: Then Leave it to me,i can make a Special Dishes for our Team in Halloween! (Rushes Into The Kitchen) F.Knight & F.Fighter: (Screaming) YAMEROOO!!!