Question

The source-filter theory provides an explanation of the ability to produce vowels (without using your vocal cords and by merely shaping your vocal tract for the production of a vowel) by introducing a voiced sound into the oral cavity.

Answer 1

According to source filter theory, speech production is two step process

• generation of sound source
• spectral fining of structures of words

They are filtered as a result of resonant properties of vocal tract.

The filtering of a spectrum source is done by vocal tract anterior to sound source. The supraglottic tract is filter for vocal source. The filters of vocal tract contain part of oral as well as nasal cavity. A filter selectively permits air to pass or block through the passage. Acoustic filter selectively decreases intensity of some frequencies and allow other frequencies to pass through them.

Sources of Voices
Sound sources	Periodic Aperiodic
Glottal sources	Voiced Whispered
Supra-glottal sounds	Planned voices Random noise