Wnewch chi – initial consonants take a soft mutation in interrogative (question) forms, e.g.

Wnewch chi adael yr ystafell?

Gaf i ddiod os gwelwch yn dda?

Brynaist ti’r car?

*Remember also that the initial consonants of verbs at the beginning of negative sentences take a soft mutation or an aspirate mutation, e.g.

Welais i mo’r bachgen.

Ches i ddim cinio.

Phrynais i ddim y car.

The table of mutations can be found by clicking here.