Thiru Navukarasar:

Thiru [meaning Respected or Sir] Navu [meaning tongue, precisely speech] arasar [meaning king]. It's a Tamil [which is a language in one of the South Indian States] word. This means, whose speech can pull people, to which God would listen.

Who is Thirunavukkarasar?

Wageshwar, was a saint who used to meditate on Lord Siva. Once he was passing by the abode of the Lord. He saw a 10 headed demon screaming in agony as his hand got struck while he was trying to lift the abode of the Lord. He wanted to Move the Huge Mountain to his place, Lanka [ Sri Lanka ] where he had his kingdom. Since it was the abode of the Lord Shiva/Siva, [ the Kailasapathi ] who pressed HIS toe and hammered the Lanka Pathi [Lord of Lanka] on that spot, which made him scream for help. Wageshwar noticed this, and took pity on him. He advised him to sing in praise of the Lord. Lanka Pathi, who's a master in singing, took his advice and plucked one of his heads and broke one of his 10 arms, and made a musical instrument, and sang for 1000 years. Lord, with mercy, appeared before him and blessed him with boons. The scream with agony brought him the name, 'Ravana'. He was blessed by the Lord with benedictions. Ravana was blessed with a Sword as boon, which feared his enemies and kept them away from him.

This Wageshwar happens to be Thirunavukarasar in his next birth. The word, Wageshwar meaning the same. [Wakku - Word, Eshwar - Saviour/Lord]