Thousands of years ago a group of people we know nearly nothing about appeared in the Middle East. We only know they spoke a language linguists call Proto-Semitic, the language from which all Semitic languages descended.
Like us, the Proto-Semitics laughed. We know this to be true because they had a word for laughter - it had the root dh.kh.k.
This group grew, split up and spread throughout the region. One group migrated south and settled in Africa where they split up into several language groups that developed into Tigrinya, Ge’ez and Amharic. In Amharic, for example, the word for laugh turned into saq.
Another group migrated eastwards. From this group, the language Akkadian developed. The Akkadians adopted the Sumerian cuneiform alphabet and were the first Semitics to write. From these writings, we learn that they called laughter chiakhu.
After these two groups had left the Levant, the language of the group that stayed in the region slowly evolved into the language that linguists call Central Semitic. The first group to splinter off from this language group migrated into the Arabian Peninsula: their language developed into Arabic. Their word for laughter became dakhka.
Years after this group diverged, another group split off and migrated northwards to Ugarit, a port city in what is today Syria. Their word for laugh became tzakhak.
And after yet more time elapsed, the group split again and formed two distinct language groups. One settled down in the area which is today the border between Syria and Turkey. Their language would become Aramaic.
The second group spread out in the area where Israel, the West Bank, Jordan and Lebanon are today. Their language is called Canaanite.
The Hebrew dialect
Later these Canaanites would themselves split up and form separate languages, which were so similar that it is more useful to think of them as dialects: Phoenician, Moabite, Adomite and Hebrew.
By the time the Bible was written, the same Proto-Semitic word had split into two words in Hebrew: tzakhak, which meant laugh and have sex, and sakhak, which also meant laugh and have sex but also meant play.
The first of these two variants - tzakhak - is the source of Isaac’s name in Hebrew, Yitzhak.
The year 605 BC is the start of the first Babylonian exile: the period in which Jews of Judah were taken captive. There in Babylonia they picked up what in the meantime had become the region's lingua franca - Aramaic.
In Aramaic that same root became gakhakh and khukh, both meaning laugh.
Even after the many of the exiled Jews returned to Palestine, Aramaic retained its strong foothold among the Jews. The Talmud was written in Aramaic. Eventually, as Hebrew died off as a spoken household language, Aramaic remained as the language of the Jews. It was to remain such for some 2,500 years.
Let us fast-forward to the end of the 19th century, when a group of Jewish intellectuals started reviving the Hebrew language. They picked and chose the different words that came out from the root we’ve been discussing in Aramaic and Hebrew, and ascribed them more specific meanings.
Tzakhak became the general “laugh”.
Gikhekh became “to laugh at”, sikhek became “to play”, khiekh became “to smile” and last but not least, in the 20th century - the Arabic word dakhka joined modern Hebrew too, with the meaning “something you laugh at”, or in high-school argot - a prank, often said apologetically, as in - "Oh come on, don't take it like that. Everybody gets a frog in their shoe. it's just a dakhka."