Reconstruction:Proto-Celtic/-tiyū

Etymology
From, an extension of with. Cognate to 🇨🇬.

Usage notes

 * The verb root is almost always put in the zero grade when this suffix is attached in Proto-Celtic.
 * Caused root-final *m to assimilate to *n.
 * When attached to a dental-final root, the root-final consonant and the suffix-initial consonant fuse to *-ss-.