The answer is...how technical do you want to get? It is a surprisingly many-layered question, and I truly hope I do not make your head explode. But it's a good question and I will try to tackle it first through the example of the name for the head god of the Iluma (our "pantheon")--the god Ilu.
Ilu is the Ugaritic word for "god". It is also the name of the head of the pantheon. Ugaritic is a Semitic language that is older than Hebrew and has its own cuneiform writing--texts in Ugaritic give us most of our sense of the Canaanite pantheon. The word ilu can be used as a proper name, Ilu, the god of our pantheon (as in "God"), or it can be used as a noun as in the god Dagan, ilu Dagan.
El is the Hebrew word for "god/God." Hebrew is, of course, a Semitic language, but it is not as old as Ugaritic, and early in its writing uses the Phoenician alphabet. It is also the name of the head of the earlier polytheistic Israelite pantheon before the Israelites went monotheist.
Sometimes scholars use the terms Ilu and El interchangeably, likely because 1) the words are inter-translatable and both come from Semitic languages 2) the name El is more easily recognizable because people know the name from biblical studies 3) most people go into studying Canaanite religion with a goal towards elucidating biblical studies 4) most people go into Canaanite religious studies while adhering to a monotheistic--often biblical--religion 5) most people go into Canaanite studies having studied Hebrew language already 6) many scholars don't view deities as real, independent deities. Basically, if someone's name was Star and she moves to Mexico, she has the option of translating her name to Estrella--which means Star--or keeping her name as Star from English.
Now add to this matter years and years of biblical bias and the very concept of biblical archaeology*, then add a matter of Greek translation (Astarte for 'Athartu), changes over time, or even interpretatio graeca and interpretatio romana and you've got a perfect storm for problems.
Interpretatio graeca and interpretatio romana are techniques used by classical scholars for "translating" a foreign deity's name by using the divine names of Greek or Roman culture. The technique was originally meant to help a reader have a quicker understanding of a "foreign god" but it has led to some awkwardness and a few dubious connections for most modern readers--sometimes Ba'lu Haddu is "translated" as Zeus, but Ba'lu Haddu is not the head of our pantheon and doesn't hold the exact same position or responsibilities as Zeus. There is the matter of 'Athtartu and Astarte, an actual translation and linguistic shift of a name from a Semitic language into Greek, but in this case it also encompasses a shifting of ideas and I'd venture to say a different goddess: 'Athtartu in earlier Ugaritic-Canaanite material is not a goddess of sex and war, but a goddess of treaties, fairness, and hunting, but has little to nothing to do with sex.
Also, we're often looking at at least at two different Semitic languages, usually Hebrew and Ugaritic, but also Phoenician. Hebrew, Ugaritic, and Phoenician aren't the same languages although they are related. It is like looking at Latin then revisiting Spanish and Portuguese. Ba'al is the Hebrew word for lord, while Ba'lu is the Ugaritic word for lord. The -u you see on a lot of the words and names in Ugaritic is called a case vowel, and it denotes whether the word is in a nominative case (as opposed to genitive case or accusative case) and indicates that the noun is a subject and/or isn't being acted upon. By the era of Phoenician and Hebrew, the Semitic languages had largely dropped case vowels.
Add to this the fact that we're dealing not just with four different languages--Hebrew, Ugaritic, Phoenician, and English--and three different alphabets. Hebrew used the Phoenician alphabet for a long time in antiquity; square script, the alphabet usually associated with Hebrew, didn't come around until much later.
Both Hebrew an Ugaritic have letters which do not have counterparts in English. And Ugaritic has three "alef" letters which signify a glottal stop in combination with one of three different vowels, but they do not use consonants (matres lectionis) to represent vowels--this differs from Hebrew which uses only one alef (which represents a glottal stop plus a vowel), but also makes use of several consonants to signify vowels. Because Semitic languages are written with just consonants, and consonants that suggest letters, the vowels may appear to be shifting or flat-out changing in the older forms of names and other words. This is because the vowels given are largely hypothetical and based on comparative studies through other Semitic languages--so this can shift as our understanding of these languages shift, or it can shift as a different scholar will have a different theory on which vowel is more correct. Basically, it is helpful to look to see if there is a similarity in the consonants.
Thus you can end up with multiple spellings--the moon god Yarikhu can look like Yarik, Yarikh, Yarikhu, Yariḫ, or Yariḫu, and that is just in Ugaritic. For a transliteration of Hebrew, you may even see "moon" translated as Yareach, Yareakh, or Yareaḫ.
Sometimes people will spell out the letters which do not exist in English, some people will use different tail-wagging apostrophes (one for an alef-letter and a different one for an 'ayin, while others will only use an apostrophe for an 'ayin and nothing for an alef), some will use consonant combinations for transliterating into English (examples: "ch", "kh", "sh") while others will use diacritics (ḥ, ḫ, š) and some computer systems don't allow for and/or misrepresent diacritics. Add to this that there are different systems of transliterating just Hebrew: sometimes people will use a -ph- instead of an -f- because the p and the f are symbolized by the same letter in Hebrew (and there is no -f-sound in Ugaritic).
(*There's no other archaeological field that combines a literary narrative with archaeology and sees it as a serious field of study. I've never seen Vedic archaeology or Chaucerian archaeology... Traditionally, the Bible has been taken as literal fact, with archaeologists setting out to "prove" it. Thankfully, this is changing, but it changes slowly.)
My sympathies to those of you who now need an aspirin.
14 Niqalu (Malatu), Shanatu 86
It is the fourteenth day of the first month of our year, the month Niqalu. It has been 86 years since the rediscovery of Ugarit, the city-state from which we have gained most of our primary religious documents. Today is the malatu, the full moon.
Persian Sybil by Guercino, 1647. Public Domain.