This phrase in Pāli has taken on the status of a mantra - it is chanted repeatedly in Pāli by Buddhists. Siddhaṃ can be used to write any Indic language including Pāli, although it is unlikely, historically speaking, that it was.
Mantra
Transliteration
sa bbe sa ttā su khi ho ntu
sabbe sattā sukhi hontu
Translation
May all beings be happy!
notes
The Wildmind online meditation site has more info on this phrase as a mantra as well as some sound files for how it sounds chanted