Learn Turkish: Onun bilime büyük bir katkısı var, hatta gençlere ilham veriyor. - She has a great contribution to science, in fact, she inspires young people.

Hatta is an escalating conjunction that translates to "in fact," "even," or "moreover." You use it to connect two related statements when you want to emphasize that the second statement goes a step further than the first. Here, making a great contribution to science is already impressive, but hatta introduces an even more impressive bonus: she inspires young people.

Why does the sentence use Onun ... katkısı var to mean "She has a contribution"?

To say someone "has" something in Turkish, you typically use a possessive structure combined with var (exists). Literally, Onun ... katkısı var translates to "Her ... contribution exists." The word katkı (contribution) takes the 3rd person possessive suffix -sı to match Onun (her).

Both bilim (science) and gençler (young people) end with an -e suffix. Why is that?

They both take the dative case suffix -e, which indicates direction ("to" or "towards"). This is required by the vocabulary used with them: you make a contribution to something (bilime katkı) and you give inspiration to someone (gençlere ilham vermek).

Why is the word order büyük bir katkısı instead of bir büyük katkısı?