The language of the ancient Egyptians was written with many alphabets, but our modern Roman alphabet was not included among them. So technically, no matter how we spell any Egyptian word, it will always be misspelled. There are many transliteration systems we use then to try to approximate the Egyptian spelling so that we will, at least, know what each other are talking about. The transliteration system used by linguists for the ancient Egyptian language uses a combination of Roman and Arabic letters with dots, dashes, and curved lines both above and below the letters to distinguish them from one another. There are two sounds denoted by a "t," but the dash used to differentiate them is impossible to type given a normal keyboard and font.
Many different people within the community deal with this in different ways. Some write all the "t" sounds as a simple "t," and so they write the word for "God" as "ntr" or "neter."
Others try to differentiate between the different "t" sounds by typing a phonetic approximation and so they would write the same word as "ntjr," or "netjer." Unfortunately, we just don't write phonetically. Some others try to add a "_" to imitate the symbol used by linguists and so they would write the word as "nt_r"/"net_er." This can be confusing so others chose to capitalize the "t" and write the word "nTr"/"neTer." None of these methods are incorrect, so the next time I'm corrected, I get to send you here!
The ancient Egyptians themselves wrote the word in various different ways. These are the correct spellings. Now, adding the "j" in between Neter, like this: Netjer, does not make it plural. It makes it phonetic. The plural spelling would either be Neteru, or Neterw. Or just screw the plural all together, because we all get your meaning.
