zhè shì shénme?

to be

Breakdown of zhè shì shénme?

• 这zhè: this
• 什么shénme: what

Questions & Answers about zhè shì shénme?

Why is the word order 这 是 什么 and not 什么 是 这?

Chinese keeps the wh-word in its normal position (no inversion). The structure here is Subject + Verb + Object:

• Subject: 这 (this)
• Verb: 是 (to be)
• Object: 什么 (what)

So: 这是什么？ literally “This is what?” equals “What is this?” in English.
Compare: 这是书。 → 这是什么？; 他是老师。 → 他是什么？

Do I need 是 (shì) here? Can I say 这什么？?

Use 是 to equate/identify with a noun. 这什么？ is not standard Mandarin (you might hear dialectal/clipped forms like 这啥？, but avoid them as a learner).
Note: With adjectives you typically don’t use 是: “It’s big.” = 它很大。 (not 它是大。)

What’s the difference between 这 and 这个 in this question?

Both 这是什么？ and 这个是什么？ are fine.

• 这 = “this” (pronoun).
• 这个 = “this one” (uses the default measure word 个), often slightly more colloquial or contrastive. When modifying a noun, you need a measure word: 这本书, 这个人, 这张票.