One looks like a “w” with straight lines (like an E that has fallen over), and the other is similar but with a tail or hook. Or something like that. Not only do ш and щ look similar, but their sounds are also close. So close that distinguishing them isn’t easy.
For what descriptions of sounds are worth: Wikipedia compares ш to ‘sh in shop’ and ‘ch in machine,’ but when it comes to щ, it hits a dead end: ‘Dutch has no words with this sound.’ The English Wikipedia entry for shcha/щ isn’t much help either: ‘it represents the voiceless alveolo-palatal fricative /ɕ(ː)/.’
Russischegrammatica.nl compares ш to ‘chocolate,’ and щ to an elongated ‘chic.’ Here, however, no difference was discovered between the two “ch” sounds.
Therefore, ш and щ make an excellent listening exercise. And (like with the letter ы) it’s also mouth gymnastics. Настасья Сетун and Марина Решетко demonstrate the sounds more clearly than perhaps needed; similarly, Natalya Gruzinova’s videos Постановка звуков Ш и Ж and Постановка звука Щ aren’t exactly easy on the eyes.
Fortunately, the animations from Maria, Katya, Anya, and Olga are much kinder (and, more importantly, helpful).
Russian pronunciation of letters Ш and Щ
(Umashi Learn Russian, 2020, 10 mins)
Pronunciation practice / Confusing pairs (Ш and Щ)
(Live Russian, 2018, 8 mins)
From the same channel: Confusing Sounds Щ Ш / Practice (2020, 59 mins) and Russian pronunciation: sounds Ш and Щ (2017, 3 mins).
Russian Ш and Щ
(Anya Golubeva, 2018, 6 mins)
Phonetic Exercises: Ш vs. Щ
(Amazing Russian, 2016, 4 mins)
From the same channel: Phonetic Exercises: “Hissing” Consonants Ж, Ш, Щ, Ч, Ц (2019, 12 mins).
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