Any beta test of a product is bound to have rough edges. Take the criticisms offered here as points to ponder.
As you do not include the language I am learning, it is not a product I would use. Still, I took the time to look through it a bit.
I did not grasp at first that when it showed “191000” and said the word “one thousand” that it had changed from flashcard mode to test mode.
I am not sure how I am suppose to indicate I know the word. I kept reviewing cards and it still said 0 correct. Hmm. Felt kind of disappointed that they system didn’t think I was learning anything.
The audio files were inconsistent. Sometimes a man, sometimes a woman, of varying sound levels. It was clear you are working off of native speakers recording each word rather than a generated audio from the IPA of the word. It will certainly make adding vocabulary difficult if you have to have someone record audio for each word.
I agree that first impression of your home page was too much text, and some of it did not read like written by a native English speaker. Perhaps you could have someone review your text and consider having much less on the first page?
I am actually studying numbers in Korean at the moment, so I used the English cards and said the Korean words. Korean has two number systems (native and Sino-Korean) so I wonder how your flash card system would handle that? In other words, for ‘3’ there are two correct answers.
I took the quick test. I was bored before finishing the 50 questions, but that could be because I knew all the answers.
It just has the look of the kind of website a student learning how to program would create as a programming assignment. It lacks the sophisticated design to make it appealing. As a beta test, I found no flaws, but I also did not see any compelling reason to recommend it until you do some further development.
The question that arises is who is your audience?
If you are just doing this as a hobby, great, have fun and don’t be discouraged by nay-sayers. I write my blog for fun with no expectation of gaining an audience. If you hope to make a commercial venture out of selling this product, then perhaps you should research your competition.