Here's why:
* Noun clauses function as nouns in a sentence. They can be the subject, object, or complement of a verb. They are typically introduced by words like "that", "what", "who", "where", "when", etc.
* Adverbial clauses function as adverbs in a sentence. They modify verbs, adjectives, or other adverbs. They provide information about time, place, manner, reason, purpose, etc. Words like "because", "as if", and "although" typically introduce adverbial clauses.
* Adjectival clauses function as adjectives in a sentence. They modify nouns or pronouns. They provide descriptive information about the noun they are modifying.
Examples:
* Noun Clause: "That he was late was obvious to everyone." (The noun clause "that he was late" acts as the subject of the sentence.)
* Adverbial Clause: "He left early because he was tired." (The adverbial clause "because he was tired" modifies the verb "left" and provides a reason.)
* Adjectival Clause: "The book that I borrowed was very interesting." (The adjectival clause "that I borrowed" modifies the noun "book" and provides information about which book.)
In summary: While "because", "as if", and "although" introduce clauses, these clauses are not noun clauses. They are adverbial clauses, as they modify other parts of the sentence and provide additional information about the action, situation, or reason.