Complex sentence: In 1988, driven by his passion for the Breton language, he became a Breton teacher in Carhaix, during which he was regularly invited in traditional music festivals such as the' (Nightfalls) and the Festival Interceltique de Lorient.
Split into simpler sentences: In 1988, driven by his passion for the Breton language, he became a Breton teacher in Carhaix. At that time, he was regularly invited in traditional music festivals such as the' (Nightfalls) and the Festival Interceltique de Lorient.