Learn French: L'équipe joue parfaitement aujourd'hui. - The team is playing perfectly today.

It is built from the adjective meaning 'perfect'. To make regular adverbs of manner, you take the feminine form of the adjective (parfaite) and add the ending -ment. So, parfaite + -ment = parfaitement (perfectly).

Could I put parfaitement at the end of the sentence, like 'L'équipe joue aujourd'hui parfaitement'?

No, that sounds unnatural in French. Adverbs that describe how an action is done (adverbs of manner) usually go right after the conjugated verb. So parfaitement must come directly after joue.

Do I pronounce the 't's in parfaitement?

You pronounce the first 't' but not the last one. Because the adverb is built on the feminine adjective parfaite, that first 't' is clearly pronounced. But the 't' at the very end of the -ment suffix is silent.

Since a team has many players, why do we use the singular verb joue instead of the plural jouent?

In French, collective nouns like l'équipe (the team) or la famille (the family) are always grammatically singular, even though they represent multiple people. Therefore, they use the singular il/elle (he/she) verb form.