A sound that cannot be heard

How to use word Inaudible in Sentences? Some Examples

Teacher's voice was so inaudible that not a single student could listen any thing of it.
Sound of Fighter plane was so high that it make any other voice in the office inaudible.
Bats are able to recognise even those sounds which are otherwise inaudible to man kind.

A person who knows everything	Omniscient
One who believes in God	Theist
One who speaks less	Reticent
A person who is above hundred years	Centenarian
One who loves mankind	Philanthropist
A speech delivered without any previous preparation	Extempore
One who is unable to pay his debts	Insolvent
One who knows many languages	Polyglot
One who eats too much	Glutton
One who looks on the bright side of things	Optimist
One who is indifferent to pleasure or pain	Stoic
A list of books	Catalogue
A handwriting that cannot be read	Illegible
People living at the same time	Contemporaries
One who believes in fate	Fatalist
One who looks on the dark side of things	Pessimist
A person difficult to please	Fastidious
A person who cannot read or write	Illiterate
A thing that is fit to be eaten	Edible
A book written by an unknown author	Anonymous
A thing no longer in use	Obsolete
One who loves books	Bibliophile
One who is present everywhere	Omnipresent
One who hates mankind	Misanthrope
Work for which no salary is paid	Honorary