There are a few people that complain about that they can't hear the L at the start. For me I can't hear the whole sentence because it doesn't seem to have a sound? (For all the other sentences sound is working fine.) This is kind of annoying when the sentence comes in a type-what-you-hear exercise.
Please help spread the word that when there is no sound, this is a Duolingo issue. There is nothing that the forum participants or even the Esperanto course team can do about it. Support supposedly knows, but it may be helpful for learners to continue to file bug reports so that they know it continues to be an issue and that people care about this.
To file a bug report, go to support.duolingo.com
To hear Esperanto go to Esperanto Variety Show on YouTube.
Responding to your concern and message, several more people listened and discussed what we heard, via a Facebook discussion group. Everyone in that discussion felt that the 'L' in 'Li' is quite acceptable. I, too, hear an 'L' that I consider fine. I also hear the low fidelity of Duolingo's internet audio, which adds a certain muddiness to every recording. This may be further downgraded by the quality of speaker/headphone used by the listener. (I'm using professional-grade audio editing headphones, at the moment.) Finally, I hear the subtle differences that normally occur in the first sounds of a word, when a speaker is waiting, holding the mouth muscles in the 'ready' positions, and anticipating, before releasing the vocal apparatus to move and produce a prepared sentence.
It's frustrating when one can't hear the sounds that the letters, or other listeners, say are there. This is part of training the ear and brain for a new language. As we learn, we learn to discard the extraneous sounds, and attend to the meaningful sounds. In normal conversation, we often 'fill in' missing sounds that are supposed to be there. This is a normal part of spoken communication, which is much more challenging when we are learning a new language.
This is a new recording. I don't actually recognize the speaker. I see why you're having trouble. I played it for my son, however, and he said - without hesitation - that the voice says "li."
Edit: Since writing the above lines, I asked other fluent speakers to view this thread (see, for example, Nekoninda's comment.) They all said they could hear the L. Then again, they all knew what the answer was before listening.
I just played it for my wife and my daughter (both experienced speakers). They both thought it said "Mi."
The particular speaker in question is generally very easy to understand (I didn't know her before yesterday, but I've since watched a lecture she gave), but if you're not getting this one, you're not alone.