The plural form of "louse" is "lice".

The command of communication skills in multiple languages is essential to any company providing goods and services on the world market.

Weakness brought on by a number of respiratory ailments had forced him just last week to announce that he was giving up his conducting career.

With horse racing and such, these are called "stakes". For this meaning the plural form is often used.

In the case of language, however, it is only the ability to talk and understand that we inherit genetically; the particular language or languages that we speak are passed on to us not by genetic transmission but by cultural transmission.

Asian religions inspire him to create splendid sculptures.

In Esperanto, adjectives end in "a", and plurals in "j".

I'm not good at multitasking.

In Esperanto, nouns end with "o". Plurals are formed with the addition of "j".

In Esperanto an adjective ends in "a." The plural is formed by adding "j."

In that exhibition you will see jade carvings by several famous masters.

Kanji have multiple pronunciations in Japanese.