What term relates to language that is characteristic of common speech?

The term that relates to language characteristic of common speech is "colloquial." Colloquial language refers to informal, everyday language that is often used in conversation rather than in formal writing. This type of language typically includes idioms, slang, and regional expressions that are widely understood within a specific community or group but might not be appropriate in formal contexts. The essence of colloquial language is its relatability and accessibility, making it a natural mode of communication in casual settings.

On the other hand, circuitous refers to something that is indirect or roundabout and does not pertain specifically to common speech. Coalesce means to come together or form a whole, often used in discussions about ideas or groups merging, and is not related to language. Coddle means to protect or pamper excessively, which again does not connect to language characteristics. Thus, "colloquial" is the most fitting term in this context.