There can be thousands of meaningful sentences and they still put the most weird ones
Why is it wrong to say, "Is there lemon in the egg?" or "Does the egg have lemon in it?" ?
Native English speakers would not start a question with "The egg, does it have ..." That's Hebrew syntax, not English. In English you need a form of the verb "to be" at the beginning, if the object of the question comes before the verb.
Is this supposed to be nonsense, or to 'egg' and 'lemon' mean something entirely different in hebrew?
They have the same meaning, but it could refer to some kind of cooked egg (boiled, scrambled...), to which some people might add lemon juice...?
The English translation is bad, but is the Hebrew sentence structure common? Would you say that instead of: Is there lemon inside of the egg? (Or similar).. If it wasn't phrased as a question it would be ok. Or if it was a follow-up question regarding a statement about a dish. (This is our lemon, egg and truffle salad. Any questions? (During a cooking class, to/from a waitress, etc.)
The egg, is there lemon inside? (Still awkward/cringe inducing, but understandable in specific contexts).
The structure is not uncommon in Hebrew. It's called משפט ייחוד (uniqueness sentence?), and the idea is to move one part of the sentence to the beginning for emphasis.
I enjoy these discussions around awkward translations. And read comments like yours. They help us to start to think Hebrew. !תודה
Thank you for giving the Hebrew grammatical term יִשְׁפַט־יִחוּד. My grammars give only the Latin term casus pendens or English expressions like nominative absolute, pendent nominative, rhetorical absolute, rhetorical exposure, topic-comment construction, focus marker, focus construction or left dislocation (pick and choose at your hearts desire ;-)). I think יִשְׁפַט־יִחוּד means something like "sentence of soleness", because the first noun stands alone without being integrated grammatically directly into the sentence.
What exactly does the sentence mean or refer to? Is it similar to "Did you use lemon when you cooked the egg?"
If I say these 2 sentences fast, do they sound the same?
הביצה, יש בתוכה לימון?
הביצה, יש בתוך הלימון?
It would sound the same, but your second option is not a full sentence - "The egg, there is in the lemon?" makes no sense to me.