A while ago I thought it would be nice to have JOSM validator do the heavy lifting for US roadway name expansions (ex: Rd -> Road) [1]. It got cumbersome to manage by hand so I wrote a little C# program to generate the rules file [2].
If your country/region has good mappings between common abbreviations and expansions I would happily generate a rules file for you.
[1] https://github.com/watmildon/josm-validator-rules/blob/main/rules/USStreetNameExpander.validator.mapcss
[2] https://github.com/watmildon/JOSM-validator-street-expander/blob/main/Program.cs#L10
@watmildon we have lots of St. and St which might be expanded to Saint but I'm not sure there's a huge call. There's a lot street signs just go with St.
@ownohmanny the check for “St” as a prefix is definitely a mixed bag based on region and such. It’s usually reasonably obvious in the United States what to do but sometimes you just have to leave it alone and let a more local mapper handle it.