I suppose that the word order of an English sentence is usually Subject-Verb-Object-Adverb as you wrote above, while that of a Japanese sentence is usually Subject-Adverb-Object-Adverb-Verb like "私は流ちょうに英語を話す｡" You can also put the words in the order of Subject-Object-Adverb-Verb like "私は英語を流ちょうに話す｡”, though. ／There are some grammatical rules of the word order in Japanese. First, you put the subject at the beginning of a sentence, which is the same as in English. Second, you put the verb at the end. Third, you put the object ahead of the verb, which is the opposite of that in English.

I = subject = 私 (は) ／ speak = verb = 話す ／ Japanese = object = 日本語 (を) ／ fluently = adverb = 流ちょうに ／

私は日本語がペラペラです。

私は日本語を流暢に話します。