Apparently, we have same issue in contrib/unaccent.
Yeah. The data structure in contrib/unaccent seems to be a plain old trie, rather than a radix trie, though. According to wikipedia at least, the difference is that in a radix tree, the edges are labeled with sequences of elements, rather than single elements. Want to patch that too?
Agree, trie is most comforming term here. Patch is attached.