Learn Hardcore Japanese: watasi ha butyou ni iken wo tutaemasita.

は is the topic‐marking particle. It tells the listener what we are talking about (in this case, 私) and sets it up as the theme of the sentence.
It’s different from が, which highlights the subject or the focus of new information.

Why is に used after 部長?

に marks the indirect object or recipient of an action.
Here, 部長に意見を伝えました literally means “conveyed an opinion to the manager,” so 部長 is the person receiving your opinion.

What role does を play after 意見?

を marks the direct object of the verb.
In 意見を伝えました, 意見 (opinion) is what you conveyed, so it’s the thing directly affected by the verb 伝える.

Why is the word order “私は部長に意見を伝えました” different from English?

Japanese follows a Subject–Object–Verb (SOV) order, unlike English’s SVO.
The verb (伝えました) always comes at the end.
Particles (は, に, を) mark each word’s grammatical role, so word order is more flexible than in English.

Can 私 be omitted here?

Is 伝えました formal or casual?

伝えました is the polite past form (–ました) of 伝える.
It’s appropriate for business or respectful contexts. In casual speech you might hear 伝えた.

What nuance does 伝える convey compared to 言う?

伝える means “to convey,” “to pass on,” or “to communicate” information or feelings with care for the transfer of meaning.
言う simply means “to say” or “to utter.”
Use 伝える when you emphasize the act of careful or formal communication (e.g., relaying someone else’s words, making a report).

How do you pronounce 伝えました, and what is its dictionary form?

Pronunciation: tsu-ta-e-ma-shi-ta (つたえました).
Dictionary (plain) form: 伝える (つたえる). The stem is 伝え-, then add polite past ました.

Does this sentence imply that the 部長 agreed with or accepted the opinion?

No. It only states that you conveyed your opinion.
There’s no built-in judgment or response implied—you only know the action was completed.