"Thursday."

Translation: Dydd Iau.

[Indicosa]

Should lau be pronounced /jai/ or /lai/?

[EllisVaughan]

The first one. (The first letter is an "i" and is pronounced like the "j" at the start of the German "ja"

[rmcode]

Yes, it's unfortunate that the Duolingo font makes it look like an 'L'.