I'm not saying $25/mo is a good price point, however, personal experience has taught me that (at least on products I've launched) increasing prices has always led to more revenue and profit.
There's (still) plenty of space in the market for boutique software offerings. I think it's his marketing that needs tweaking, not the pricing. Getting better copy and better targeting could mean 10x more revenue, at which point he can think about cutting prices.
I'm also merely giving my feedback as someone who (1) has a very good salary (2) enjoys readlang and uses it nearly daily (3) enjoys supporting indie software developers, that even I personally would balk at paying such a steep price, as the value would not be worth it to me.
I think feedback from consumers like myself can be valuable, as I also know others who use readlang, and none of them have anything more than a part-time job or PhD stipend which would price all of those people out of the software as well.
Also, I did not say to tweak the pricing, I was responding to the suggestion above to raise prices 5x what they are currently, and that I thought it was a bad idea.
I've been using readlang for about a year now, and while I love the product, would never pay $25 a month for it.
It's a great product, but $25/mo is 3x more than a netflix subscription, over 2x the cost of 1TB on Dropbox, etc.
This not to mention that the vast majority of users are students and people trying to train themselves to be able to work or study in new countries.
Hundreds of dollars a year might not be a lot to you, but I assure you it is for the vast majority of people who would want this product.