I’ve experienced serious lagging in the Wikipedia iOS app for many years. When typing in the search field, it would freeze after 2-4 letters for several seconds. The same happened when scrolling through articles.
I have 7 languages enabled, and I suspect the app struggles with generating Explore feed suggestions across multiple languages.
Disabling the Explore feed appears to have solved the problem.
If you’re experiencing similar issues, try this:
Settings -> For you -> What’s driving your feed -> Languages -> Customize your feed
Here you can turn off the languages you don’t want feed suggestions for, or all of them if you don’t use the feed (I don't).
I’m curious: Do others experiencing these freezes also have multiple languages enabled? And does disabling the feed solve the problem for you? I'll send a bug report if others can confirm this.

Anhedonia is common in people who are dependent upon any one or more of a wide variety of drugs, including alcohol), opioids, cannabinoids, and nicotine. Although anhedonia becomes less severe over time, it is a significant predictor of relapse.

they tried to remove her Wikipedia page!

MARTINA DIMOSKA IS a scientist, originally from North Macedonia, who works at NASA’s Johnson Space Center in Houston. 

I use wikipedia a lot for sports statistics and I've never seen such a glaring oversight. it's so weird because usually Wikipedia is so reliable and this is an unimaginable error to make. Every website lists James Harden as the leading scorer in 2015-16 except Wikipedia. How do we fix this?

Let me know, thanks!

List of NBA annual scoring leaders - Wikipedia

2015-16 NBA Player Stats: Totals | Basketball-Reference.com