Which term has three aspects to its study: language form, language meaning, and language in context?

What term can we refer to when a particular ethnic group has a particular set of sounds produced in a particular language and distinguishable by native speakers of that language from other sounds in that language.

What terms best represents when we think of the[t] sound in words such as tar, star, writer, butter and eighth as actually being "the same," even though they are all very different from each other because of the relationship to the other sounds around them?

What term best describes when two people from different backgrounds and different languages are trying to interact with one another?

Which term enables speakers to distinguish among possibilities such as the following terms: Hey! and Excuse me! to get someone's attention in English?

In the following sentence, the verb tense was changed. In doing this, the sentence was changed to correct format. What correct term are we describing?
Incorrect - We are not allowed smoking in the restaurant.
Correct - We are not allowed to smoke in the restaurant.

The following are examples of what term ? One man’s trash is another man’s treasure. Some see the glass half empty and others see the glass half full.