"Cet oiseau mange du riz."

Translation: This bird is eating rice.

[Sue_Parkes]

Heard this as plural, what hints should have given me the clue it was a singular bird?

[CommeuneTexane]

You would hear ces oiseaux for more than one bird. Note that there is a liaison between the words and the s makes a z sound, ce-Zoiseaux.

[EdRNod]

I speak clearly, and the program doesn't recognize half the words. It picks up mange du riz, but won't hear cet oiseau. I think Duo needs to look into the voice recognition. My microphone is turned all the way up. So shall I shout?

[Mister.Ed]

the phrase is correct with the exception of the capital letter on the the word This.

[CommeuneTexane]

Capitalization doesn't count against you when you answer a sentence. Perhaps there was a typo?

[Michel199948]

Call me stupid, but shouldn't is be: 'Ce oiseau mange du riz'?
So 'ce' in stead of 'cet'?

Thanks for your help!

[CommeuneTexane]

Hardly stupid!

Oiseau is a masculine word, so your line of thinking is correct. However, for euphonious reasons (it sounds better), when there is a determiner (ma, ta, sa, ce) or adjective (beau, nouveau) next to a noun beginning with a vowel, these words change to have a consonant at the end. It is like "an" in English. Instead of "a" it becomes "an" next to a vowel sound, same concept.

Examples:
ce + oiseau → cet oiseau
ma + amie → mon amie
sa + idée → son idée
beau + appartement → bel appartement
nouveau + artiste → nouvel artiste

[Michel199948]

Thanks for the extended explanation! Now it becomes clear to me.

The point is: I'm Dutch and have to learn French in English language, but... I speak Dutch as my native language.

So, from translation to translation to translation... and back. ;-)

[CommeuneTexane]

My pleasure.

Learning French from English (as a second language) is an extra challenge, hats off to you!

Please don't hesitate to ask questions in the future as well. I think you will find people more than happy to help. :-)