A Mantra is a special set of words through only that particular deity could be summoned. If I write or speak in Chinese you won't be able to understand and my words will not produce any effect. But if I speak the language you know its effect shall be with doubt. Praying to these deities in one's language won't help much but if one uses the words that they can understand the result shall be instant.

These words are the Mantras evolved by Rishis and Yogis who actually prepared them and used them to prove their worth. Over the ages these have helped thousands of Sadhaks achieve even that which appeared impossible to them. Within doubt that whose chanting fulfills one's wish is a Mantra

The Use of Mantra:
A mantra is an invocation, containing a sacred syllable or set of syllables. When a mantra is uttered with specific rhythm, with sincerity of devotion and purity of thought and action, and with phonetic and grammatical accuracy, in a manner prescribed by the scriptural injunctions of the Vedas or some authoritative scripture, it is believed to invoke a particular deity and compel the deity to assist the invoker to achieve a desired end. It is interesting to note that according to Hindu beliefs, if a mantra is pronounced correctly the deity to whom it is addressed has no choice but to respond to the invoker automatically and help him.

When a complicated ritual such as a soma sacrifice or some other yajna is performed, not one but many deities are invoked simultaneously by groups of priests chanting various mantras. Their chanting creates the necessary vibrations in the atmosphere to awaken the deities and facilitates their descent to the place of worship.

The sound that is generated by the chanting of the mantras is very important, but is is not the only requirement for the yajna to be successful. The remaining requirements are the appropriate use of tantra and yantra, which will be explained later.

It is believed that hidden in each mantra is the energy of a particular deity which remains normally latent, but becomes active the moment the mantra is pronounced accurately in the manner prescribed by the shastras. The divinity awakens only if the vibrations generated by the chanting matches with its basic frequency. Besides this, as we have already noted, the appropriate use of tantra and yantra must fit in the overall purpose of the worship and remain in harmony with the expectations of the divinity to whom they are directed.