Perhaps you should read over the entire story again and see how the myth entails the entire World.
Either way, it is an unsubstantiated belief.
I know the story and in no way does it come close to entailing the whole world. For instance lets just jump to the end
Genesis 10:1-5 -
1 Now these are the generations of the sons of Noah, Shem, Ham, and Japheth: and unto them were sons born (8735) after the flood.
2 The sons of Japheth; Gomer, and Magog, and Madai, and Javan, and Tubal, and Meshech, and Tiras.
3 And the sons of Gomer; Ashkenaz, and Riphath, and Togarmah.
4 And the sons of Javan; Elishah, and Tarshish, Kittim, and Dodanim.
5 By these were the isles of the Gentiles divided in (8738) their lands; every one after his tongue, after their families, in their nations.
Now some "global" flood kills everyone in the whole world except those in the boat and somehow they are dividing the isles of the gentiles. Also these seven people in the ark, did they all speak after different unique tongues? After their families? Arent they the sons of just one family, Noah? And somehow they had their own nations
I am well aware of Concordances and Lexicons. I am also aware of Christian apologetics and reliance on unsubstantiated belief.
If so then you should know not to fully rely on one translation