"Ele sempre lê uma revista."

Translation: He always reads a magazine.

[saniac]

At full speed I can't tell this from "eles sempre leem a revista." Is that a mistake a native speaker could make?

[Paulenrique]

At a fast speed le and leem seem similar, but A and UMA are pronounced very differently and with a little more attention you can tell them apart ;)

[Danmoller]

The "M" a the end of the words does not "close".

"Leem a" is not spoken as "leema", but as "leenha"