Morgoth did not have a son. The quote you mean is this one:

"Gothmog 'was a son of Melko and the ogress Fluithuin and his name is Strife-and-hatred, and he was Captain of the Balrogs and lord of Melko's hosts ere fair Ecthelion slew him at the taking of Gondolin. The Eldar named him Kosmoko or Kosomok(o), but 'tis a name that fitteth their tongue no way and has an ill sound even in our own rougher speech, said Elfrith [emended fmm Elfriniel].' (In a list of names of the Valar associated with the tale of The Coming of the Valar (I. 93) it is said that Melko had a son 'by Ulbandi' called Kosomot; the early 'Qenya' dictionary gives Kosomoko = Gnomish Gothmog, I.258. In the tale Gothmog is called the 'marshal' of the hosts of Melko (p. 184).) In the later development of the legends Gothmog was the slayer of Feanor, and in the Battle of Unnumbered Tears it was he who slew Fingon and captured Hurin (The Silmarillion pp. IO7, I93, 195)."
Bolt 2

Bolt is an erarly draft of Tolkien's world and is not much excepted as Lore. Tolkien's original idear of Balrogs is that they were a complete race, thousands strong. Only later did he change them into Maiar and only 3-7 ever existed.

"The early conception of Balrogs makes them less terrible, and certainly more destructible, than they afterwards became: they existed in 'hundreds' (p. 170),* and were slain by Tuor and the Gondothlim in large numbers: thus five fell before Tuor's great axe Dramborleg, three before Ecthelion's sword, and two score were slain by the warrior's of the king's house."
BoLT2, Commentary by CT on The Fall of Gondolin

"* The idea that Morgoth disposed of a 'host' of Balrogs endured long, but in a late note my father said that only very few ever existed - 'at most seven'."
BoLT2, The Fall of Gondolin

In short Gothmog was meant to originally be a son of Melkor, but later Tolkien changed this idear and made him into a Maiar. Therefore only Gothmog's name means 'Son of Melkor' or 'Voice of Melkor'.

Hey Lord Of All,

Thanks for your post. Yes I knew that it was one of Tolkien's earliest concepts which were later abandoned but I just wanted to delve deep it this topic mainly to see what Tolkien's main thoughts led to such writing at first.

Please keep on posting!

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Don't worry I have not gone anywhere but my main commitment is to Tolkien Forums.

I tend only to participate in topics of Lore. Opinion and fun threads hold little interest.

But in Lost tales it says taht Luthien wove a more powerful spell of sleep over her cloak than her mopther could ever weave. Maybe in certain cases where illuvater made , like Feanor an elf with similar skills of hand and lind ot the maier thamselves and maybe Thingol was one of these. This is just my opinion and Im just throwin it in for sheer interest in how the topic will turn.

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"This is the hour of the Shire-folk, when they arise from their quiet fields to shake the towers and counsels of the Great. Who of all the Wise could have foreseen it? Or, if they are wise, why should they expect to know it, until the hour has struck? "

Gothmog did not mean 'Son of Melkor' however -- as noted in the first part of your post, where you quoted that it meant 'strife and hatred' in The Book of Lost Tales. And (just for clarity) Gothmog as meaning 'Voice of Goth (Morgoth), an Orc-name' is from a 1930s wordlist.

In other words (short version): in The Book of Lost Tales, Qenya Kosomot, Kosomoko, Gnomish Gothmog meant 'Strife and hatred', not 'Son of Melkor' -- nor 'Voice of Melkor' here at least. And these are Elvish names of course.

Later in the 1930s we find Gothmog meaning 'Voice of Goth' and so on. But in the Etymologies of the later 1930s early 1940s we again find Gothmog -- according to this text, where we still have not yet reached the Sindarin of The Lord of the Rings, Gothmog was said to hail from *Gothombauk- from a base MBAW- 'compel, force, subject, oppress.', and GOS-, GOTH- 'dread'.