Deeply devoted to Lord Siva, the Divine Name of his favorite Lord constantly played on his tongue. How deep was Nandanaar’s yearning for his Lord! Today, we speak of ‘Nama Siddantha’. It was Nandanaar who first propounded ‘Nama siddhanta’! He gathered the people in his neighborhood and pleaded with them to sing the Name of the Lord
He pleaded, “Chant Namah SivAya! Namah SivAya! Chant Umapathe! Chant SAmbasivAya!” The people of the slum objected and refused to chant the Name of Lord Siva while they had their own deities.
They said to him, “Nanda! Why do you insist on our chanting tongue twisting Names?” But Nandanaar was not to be bogged down by their disinterest and opposition. Amidst them lived a dumb girl who everyone called ‘Oomacchhi’ (dumb girl in Tamil language).
Nandanaar advised the people, “Say ‘Oomacchi vA’!” (oh, the dumb! come!). So, they all called out to her, “Oomacchi vA! Oomacchi va!” and it sounded as ‘Uma Ch(S)iva!’ Nandanaar thus succeeded in making the Lord’s Divine Name play on the tongue of those who could not even utter it! In this way all the people around began chanting the Name of the Lord.
Please check these: Excerpts from a discourse by our Sri Sri Muralidhara Swamiji