Irish Gaelic orthography – or the way words in the language are written and spelled – has not always had the current Latin (Roman) standard typeface that we are used to with English, French and so on.
In earlier times, up to the mid 19th century, Irish Gaelic was written in a scripted hand (typeface) with several of the letters quite different from what we see today. However, it is the same Latin alphabet that was used with some (particularly the R and the S) simply having a different shape. Did you know the Gaelic alphabet only has 18 letters (and 5 additional, accented vowels) ?
These scripts then (or fonts) are referred to as clónna, namely seanchló or Cló Gaelach, now mainly used for signage (see above) and decorative or commemorative purposes. Some interesting information about Irish writing and the changes our orthography have gone through can be found on the Nua Leargais website and some Seanchló fonts are available for download here.