I also find it hard on the eyes. It is an extra layer for the eyes as well. Wait after you will have thousands of lines read that way than you tell me. For casual users might be not a problem, but for the others…
I use the level 4 too to remind me of words that have more than 1 meaning, and that I find it hard to remember. With these thick underlines it becomes more difficult to spot them. An extra effort for the eyes that I personally don’t need.
Just a switch on/off would do.
I like this feature a lot, especially on the mobile app. 
I like it too. I think it’s very useful for all the reasons others already mentioned.
I’m starting to change my mind. I didn’t like it very much at first, but I used it today on my e-reader (which has a much bigger display than my phone), and I actually liked it. I guess it might be too thick for smaller displays. Perhaps settings of the line would be useful.
To me it’s a terrible distraction, especially as it not always following the text, adding up to the beta-feeling of this software as a whole.
It also seems to consume a lot system resources, everything being a lot slower now. With this feature (or other “features” I can no longer edit LingQs on the fly - opening a yellow or blue word now takes approximately 25 seconds , so I need to pause the audio every time I want to click on a lingq. Wish it could be turned off.
just in case, I added this support request to add the settings to turn it on/off like on iOS: https://forum.lingq.com/t/missing-setting-for-turning-onoff-underline-text-in-webapp/183203/
Another thing, it seems it is not consistent. Today I have noticed that sometimes there was a line, sometimes there wasn’t! This is creating an additional distraction.
Plus, I don’t understand why this underlining is present when we are in sentence by sentence mode.
I thought I could temporarily get rid off it in sentence by sentence mode, by playing the audio and clicking the arrow to advance, but the underlining appears there too, which doesn’t make any sense. Imho.
I noticed that when I pause and unpause the audio, the line often disappears for a while. That’s a pity, because of course that’s exactly when I could often use help finding my place again!
In general, I strongly agree with making it optional – for my own part, I like it, though!
If it was a continuous line, it might be alright, but we should still be able to turn it off. Underlining each word is highly distracting to me.
I like the idea of it, but the heavy black line is too overpowering (I can’t imagine a double black line), and I would also like to option to turn it off (because,as much as I think it’s a good idea, it is distracting and I will turn it off).
I think it could be useful, but I find it distracting as it is often not in sync with the audio. An on/off button would be a welcome addition to this feature.
I do agree with this. I wish it were continuous, like on the (iOS) app.
Thanks for all the feedback! This feature is mostly helpful for beginners in the language who have a hard time connecting the spoken word to the written word. We do plan to add a setting soon on web, like we have on iOS, to turn the audio underlining off and change the style.
I think it be great if you could toggle it on or off. I think it be great for a language your just learning but past intermediate i think it just gets in the way
maybe a highlighted version would be better
i love the feature but i agree there should be an option to turn it off
I like the feature for the following reasons
I also concur that this should be a feature that you can turn off.
I have a lot of 4 level words can not see them properly under black line. It is better if they give it a try to one of the above mentioned advice by changing the color from black to green or something else which is easy on your eyes. I do not know if it fixes the issue but worth a try before offering the turn on/off option.
I like this feature because sometimes i can’t fallow the sentence while listening, but if there is somebody doesn’t like it, there should be a botton to turn it off.
Like there isn’t an obvious not crazy way to go, like turning this experimental thing off first and then plan to add an option to turn it on if you find this helpful.
There’s a reason why it’s not regular text that is underlined, but links. It’s a mean of making typographic visual accents on the information you’d like people to pay attention to. Imagine reading a book, I mean, oh c’mon, guys, nice trolling… or I can’t believe you’re serious 
It doesnt seem to accurately line up with the audio a lot of the time which makes it incredibly distracting.
It sounds melodramatic but i simply cant use the audio features while its in this state because its too distracting. I realllllly hope theres a toggle function soon.
For now im just reading without audio.
