Here's why:
* Participle: A participle is a verb form that acts as an adjective. In this case, "speaking" is the present participle of the verb "speak".
* Participial Phrase: A participial phrase is a group of words that includes a participle and its modifiers. It functions as an adjective, describing the noun or pronoun it modifies.
In this sentence, "speaking as loudly as possible" modifies the noun "Curt" and tells us how he spoke.