Takes two arguments, but the second one is not needed (but possible for compatibility with the lenition template, and for future expansion of the concept)
So it can be called as either {{/sga-nasal|word}}, {{/sga-nasal|w|ord}}, or {{/sga-nasal|w}}ord: makes no difference to the result.
Owing to some frankly ridiculous restrictions in the programming environment for string manipulation, this requires the first letter to be split off. It does not check for a string longer than 1 character. An initial consonant of longer than one character isn't an issue in Irish, but can come in to play for, eg., Breton.
Must be supplied with the first letter split off from the rest. The rest of the word should be the second variable: {{sga-lenite|w|ord}}. Do not put it outside the template as {{sga-lenite|w}}ord, as lenition is suppressed for [s] followed by [c], [m], [p] or [t]. If the rest of the word is extracted, then this case cannot be detected.