• Hello = Shwmae / S’mae
• Good morning - Bore da
• Day - Dydd
• Yes - ydw, ydy (and other words, it’s a bit complicated)
• Correct - iawn
• Goodbye - hwyl
• Boy = Bachgen / Hogyn (South Wales / North Wales)
• Girl = Merch / Hogan (South Wales / North Wales)
• Motorway - Traffordd
• Shop - Siop
• Phone - Ffôn, mobile phone - ffôn symudol
• Banana - Banana
• The - y, yr
• A - (no article)
• You - chi / ti
• We - ni
• Us - ni
• Him - o
• Her - hi
• Them - nhw
• Up - i’r lan
• Down - i lawr
• This - hon / hwn / hyn
• that - hyna
• those - hwnnw

I can’t be arsed to write the pronunciation in IPA. Just go on Google Translate or learn Welsh on Duolingo.