Our body, the ions moving in the atmosphere generates sounds by collision of molecules, this collision can be for the transfer of the energies or can be due to random motion caused by external factors, like air in the atmosphere and generation of emotions. These sounds are observed, analysed and then reacted upon by our sensory system which is controlled by the brain, so wont be wrong to say, if active, then brain is the one which prepares the system with the changes which are occurring within or in the close ambience.
These sounds which are being observed by the brain can be experienced in deep meditative state, which would have been the case with the meditative sages, who observed the changing behaviour of the sub conscious brain and analysed the forces which were triggering those changes keeping in purview the benefits, and hence the germination of phemes, which are referred as beej (seed/reason) in the vedas. These beej mantras stimulate specific energy points within the human system, these energy points are 114 chakras which regulate and shape the life, both societal and spiritual aspect of life of each and every person.
During the course of time, several of these beej mantras were strategically combined in a specific manner to obtain prescribed results, like triggering of specific type of energy within the system to achieve something in particular (in all probabilities the reason would be as each and every organ within the human body is meant for performing a specific work). As the society evolved the link with the natural sound was replaced with language, and hence as per the demand from the society the meanings of these mantras kept growing, hence the people translated those sounds into words and thereon deriving their meanings which would lead to activation of certain kind of emotion, reward or fear.
The author doesn’t subscribes to deducing the mantras into words and then being aware of their meanings, only triggers emotions and hence the sense of fullness but doesn’t causes the biological transformations, as what is the basic tenet of reciting or chanting the mantra is.
While recitation or chanting of the mantras, the person should be versed with the pitch, tone and frequency of how the mantra should be chanted or recited, as wrong recitation wont result in enhancement of the energy and hence the rise or fall in the body temperature will not happen, which in itself defeats the reason of expediting it. In addition to learning the right way of recitation, you should be aware as what is the prevailing energies within you and what is the correct mantra which will be suitable for you for achieving that specific goal, as the ethos is in each and every scientific methodology, in this too, the correct choice and correct recitation is the key, the mantras or its recitation cant be chosen by a person by keeping into consideration the “emotions” associated but with the biological gains (the gains in the energy and strength).