Writing Yivalese from the spoken form into its written one is an interpretive process. This is due to phonetic and semantic drift from its original source which was fairly consistent, until it wasn't. For example, Niwiden, the word for Nest, has over time been crunched to Nuden, which can be written in a few ways (XWwy (XWwy) for its logographic form, NyWyDn (NyWyDn) for historic purposes, and NwDn (NwDn) for a shorthand version (think through vs thru)).

Once you have selected a compound of glyphs to represent a concept - such as GxDl (GxDl desire+tell = song) - you may backform the pronunciation by extracting specific characters from those pairs. It is also fine to mix and match to keep the resulting pronunciation natural, with the guiding principle to use semantically related character wherever possible.