"I do not want toys."
Translation:Dw i ddim eisiau teganau.
Eisiau is one of the very few verbs that doesn't need 'yn' as a connector.
The reason being that the expression 'I want' originally used 'eisiau' as a noun meaning 'wanting'.
Mae eisiau tegan arna i = 'There is wanting a toy on me'
This has simplified to Dw i eisiau tegan.