Over the last few weeks, the company behind the popular Duolingo language learning app has rolled out an overhaul to its user interface and experience, sparking intense criticism from some longtime fans of the app and in the large Reddit community devoted to it.
Duolingo's CEO, Luis von Ahn, has seen those concerns, and he has no plans to undo any of the changes.
“This is why we decided to do this: to simplify Duolingo and also to make it so that new users understood how to best use Duolingo,” von Ahn said in a video interview.
In the previous version of Duolingo, users worked through a tree of lessons, where completing one unit would open a series of other lessons that users could choose between. As users progressed, they were encouraged to go back and forth between the various topic units to continue to progress up their tree.
In the new version of Duolingo, the company has instituted a single learning path for users to move along, eliminating the ability to choose which new lesson to take next.
Software redesigns often spark a certain amount of user backlash, but the passionate response from parts of the Duolingo fan base has been particularly intense.
A Twitter search for content related to the update brings up dozens of tweets from users who have called it "the worst update ever" and compared the new style to the mobile game Candy Crush.
Some users have even taken to campaigning against the update, attempting to get the company's attention with one-star reviews in the Apple App Store and social media posts tagging the company.
The backlash also highlights just how successful Duolingo has become. The app, which is free to use, says it has built up a user base of more than 500 million people since it launched in 2011. It currently offers lessons in more than 30 languages.
Tobi Fondse, 50, who lives in the Netherlands, started a dedicated Twitter account called Duo Is Sad in an attempt to get the company's attention.
Fondse, who said he had used the app daily for 449 days before the update, said he was caught off guard by the update and is upset that his choices of lessons were being limited.
"I think I will be less engaged, and that's mainly because sometimes you just want to do some easy lessons because you're tired," he said.
Thomas Wilson, 32, a visual effects artist and video game art director currently in Cyprus, also said he felt limited by the new update and was concerned that it doesn't align with his learning style.
"I don't believe for a second that there's one way to learn language, and it seems like that's what they're trying to tell us," he said. "It's the opposite of inclusive, in many ways, kind of problematic."
Wilson said he has been using the app to learn Greek in anticipation of his wedding, where he'll be marrying into a Greek family. Now, he said, he's worried he'll become demotivated, noting that currently the Greek lessons are lacking informational functionalities like lesson guides that were included with some of the other languages in the update and have been touted by the company.
In press materials about the update, the company explained that the single learning path integrates strategically timed reviews of certain content that it said are optimized for learning and memory — something that was previously at the user's discretion.
"The two goals that we had were decreasing confusion and increasing learning outcomes," von Ahn said.
According to von Ahn, the company anticipated backlash over the update because they experienced similar pushback over their last big changes. Von Ahn said that for this reason, the company strategically rolled out the new update to new users first, gauging their engagement with the app and getting early input into areas for improvement.
"I think it's important to listen to your feedback," von Ahn said. "But I think it is important to realize that people are change averse."
Many of the critics who spoke out online and to NBC News said they'd like to be able to revert back to an older version.
Von Ahn shot down that idea.
"I understand why you may want that," he said. "We do think that the new system is better. And, you know, for us, having to maintain two separate systems is pretty difficult."
Regardless of the criticism, von Ahn and the company maintained that the vast majority people are on board with the update, pointing to some positive tweets about the changes and claiming that internal metrics indicate equivalent engagement with the updated interface in comparison to the old one.
For people who aren't happy with the update, competitors are swooping in. Duolingo competitor Babbel has been replying to tweets about the update, offering to assist users looking to make a transition.