Abarim Publications' online Biblical Hebrew Dictionary
The two verbs צחק (sahaq, as the common transliteration goes; this word would probably have sounded as tzachaq) and שחק (sahaq or rather sachaq) are obviously related and mean the same thing: to laugh.
An alternation between the letters צ (tsadhe) and שׂ (sin) is rare in Hebrew. The form צחק (shq) occurs in Genesis, once in Exodus and once in Judges. The derived noun is used only by Ezekiel. The form שחק (shq) is used from the book of Judges (three times) onward. Curiously, only one name has been derived of both forms, namely Isaac. The name Isaac is spelled יצחק (yshq) in the Pentateuch, Joshua, Kings and Chronicles. The alternate version, ישחק (yshq), occurs in Jeremiah 33:26, Psalm 105:9 and Amos 7:9 and 7:16.
Some scholars (HAW Theological Wordbook of the Old Testament) consider these two forms as alternative spellings of the same verb, while others (BDB Theological Dictionary) consider these two forms as two separate verbs. Here at Abarim Publications we figure that the Bible writers commonly wielded such a high degree of precision that their choice between these two forms probably has meaning.
The two forms occur in close proximity of each other only in Judges 16, where Samson is made fun of by the Philistines. The form צחק (shq) occurs in Judges 16:25. The form שחק (shq) occurs in Judges 16:25 and 16:27.
The verb צחק (sahaq) means to laugh, or rather: to have fun, in pretty much the same range of applications as in English (Genesis 39:14-17, Exodus 32:6, Judges 16:25).
The first people to laugh in the Bible are Abraham (Genesis 17:17) and Sarah (Genesis 18:3, 21:6), but when Ishmael, the son of Abraham with Hagar also starts laughing, Sarah drives him and his mother out (Genesis 21:9). Sarah's son Isaac is named after the verb to laugh, and as he marries Rebekah, he appears to have ways to make her laugh as well. That their 'laughing' wasn't restricted to mere merriment is attested by the outcry of the local king Abimelech, "Behold, certainly, she is your wife!" (Genesis 26:8). The context does not reveal whether Isaac and Rebekah were making love or whether the two were having a connubial brawl in which Isaac derided Rebekah.
This verb's sole derivative, the masculine noun צחק (sehoq), laughter, occurs only once in the Bible, in Ezekiel 23:32.
The verb שחק (sahaq) means to laugh or have fun as well, is used more than the alternate form and (possibly because of that) seems to have a broader range of application. Apart from laughing at in mockery (Job 30:1, Lamentations 1:7) or expressing joy (Proverbs 8:30-31), this verb may applied as broad as to mean to entertain (Judges 16:27) or even to play in a competitive setting (2 Samuel 2:14). This verb is also applied to express festive merriment (1 Samuel 18:7, Jeremiah 15:17) or the frolicking of animals (Job 40:20).
This verb yields two derivations:
- The masculine noun שחק (sehoq) or שחוק (sehoq), meaning laughter (Job 8:21), derision (Jeremiah 20:7) or a game or sport (Proverbs 10:23).
- The masculine noun משחק (mishaq), which denotes the object of derision (Habakkuk 1:10 only).
A note on laughter
Laughter, like speech, is an acquired ability which developed in our past for reasons that have long been obscure. This obscurity in turn was due to the obvious fact that laughter is a continuation of the fear reflex — that's why it's so contagious, so hard to stop when you're at it and often so unclear whether someone is laughing or crying: it's basically the same sound produced by the same body parts.
In the last few decades, the study of natural synchronicity has made the connection clear. Humanity's incredible success in the world is not due to our intelligence, but much rather to our ability to tune into each other: synchronicity, or the mentally blending together at the reflex and subconscious level. Many closely monitored and double-blinded experiments have shown that humans (and particularly kin and romantic partners) have the ability to synchronize their heart beat, skin conductivity and even general mood. Women living together often menstruate at the same time.
In the natural world, one "naked ape" isn't much of a foe, but fifteen of them could be problematic, unless of course these fifteen don't want anything to do with each other. Should they, however, demonstrate a very high level of synchronicity, namely by exclaiming their alarm cry in utter synchronicity (perhaps even in multiple voices and snazzy rhythms, hence vocal music) any enemy with any sense at all will realize that the group is not simply fifteen times a naked ape, but rather one super-organism like a dragon with fifteen heads and a transparent body.
Human singing and laughing originated not in entertainment but in shows of force and are similar to an animal's standing upright, showing teeth or flapping brightly colored feathers. The name Abraham means Their Strength (or They Are Now Protected) and expresses international synchronicity. His son's name Isaac means Laughter.