Learn Hardcore Polish: Prelegent mówi o nowym projekcie. - The speaker talks about the new project.

prelegent is a formal term for a speaker or presenter, especially at conferences, seminars, or lectures.
mówca is a more general word for “speaker” (someone who speaks), often used in everyday contexts.
Use prelegent when referring to someone giving a prepared talk or lecture.

Why is the verb mówi followed by o and what case does o require?

The verb phrase mówi o means “speaks about” or “talks about.”
In Polish, the preposition o requires the locative case (also called the 6th case).
That’s why the noun after o appears in its locative form.

Why is nowy projekt changed to nowym projekcie?

Because in the locative case singular masculine, nowy projekt declines to nowym projekcie.
Declension pattern for adjectives+nouns in locative singular masculine:

Adjective nowy → nowym
Noun projekt → projekcie

Why are there no words equivalent to “the” or “a” in this sentence?

Polish has no articles. Context and word endings carry the nuances that English articles express.
You simply say prelegent mówi o nowym projekcie without adding any article.

Is the word order fixed? Could you say O nowym projekcie mówi prelegent?

Yes, word order in Polish is relatively flexible due to its case system.
You can say O nowym projekcie mówi prelegent to emphasize o nowym projekcie (“about the new project”).
The basic SVO order (Prelegent mówi o…) is most neutral.

Are there synonyms for mówić o, and would they change the meaning?

Yes. Common alternatives include:

opowiadać o – “narrates/tells about,” more descriptive or story-like
rozmawiać o – “converses about,” implies a dialogue
wypowiadać się na temat – “expresses oneself on the topic of,” more formal
Each carries a slightly different nuance but still uses the locative after o or requires na temat
- locative.