YES... Now what's next?

Question

Here are some letter sequences, following a very similar rule. The ordering of the sequences may help you solve the sequences. Good luck!

1.

Y E S _ _ L _ B J _

2.

U D T C C S _ _ _ D

4.

E _ T C _ C S _ N D

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P.S.: All errors are intended. Please comment before you edit. Thanks!

P.P.S.: This is my first sequence problem. All constructive feedbacks are welcome.

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Hints:

Answer 1

These must be

Initial letters of names of numbers 1-10 in various languages

1. Y E S _ _ L _ B J _

Yī, Èr, Sān, Sì, Wǔ, Liù, Qī, Bā, Jiǔ, Shí
(Mandarin)

2. U D T C C S _ _ _ D

uno, dos, tres, cuatro, cinco, seis, siete, ocho, nueve, diez
(Spanish)

4. E _ T C _ C S _ N D

ek, do, teen, char, panch, cheh, saat, aath, nao, das
(Hindi)

And the irregular numbering, judging particularly from the missing three, most likely refers to

the language's rank on the list of "most native speakers"; number three on that list is English, which would have been a dead giveaway.