This lesson uses the information by The Second Nazgul, Witch-Queen Of Angmar, maybe the only member of Black Speech Community who knew Scatha:

In previous lessons adjectives, prepositions, etc. were spelled as separate words or suffixes separated by hyphen. But experienced language users usually write them in one long word. Why? Alphabets of Middle-Earth has no hyphens, so prepositons really shall be written without it. Tolkien himself wrote “sharkû” instead of “shara kû”, so joining adjectives to nouns shall be a common practice.

Many people were confused with referring to two separate people in third person and with many word modifiers (adjectives, pronouns, prepositions, etc.) in one sentence even without attaching them all into one word. So here is The Second Nazgul's answer to their questions:

“I know what you mean about referring to two different people in third person. I also found that frustrating at first, but thing is, it's often clear from context which person you are talking about – here black speech differs from English, as you can leave the subject understood with no pronoun – or you can simply repeat the noun, which is the simplest and easiest solution. Though the latter does get repetitive after a while, it's not such bad form.

Okay, as suffix word-order goes

fulug-tab-ishi = in his house
fulugugaz-tab-ishi = in his small house1)

Indirect objects are tricky. They're one of the most difficult and frustrating aspects of the language, so bear with me:

  1. If the direct object is a pronoun, and the indirect object is not a pronoun, the direct object is attached to the verb and the indirect object is separate and follows. The suffix -u is attached to the indirect object.
    Thrakul Scathazu = bring them to Scatha.2)
  2. If the direct object is not a pronoun and the indirect object is a pronoun, the indirect object is attached to the verb with the suffix -u and the direct object is separate and follows.
    Thrakulu nazgu = bring them rings3)
  3. If neither the direct nor the indirect object are pronouns, the indirect object comes after the direct object. Both are separate from the verb. The suffix -u is attached to the indirect object.
    Thrak nazgu Scathazu = bring Scatha rings4)
  4. If both the direct and the indirect object are pronouns, the direct object is attached to the verb and the indirect object follows. The suffix -u is attached to the indirect object.
    Thrakul izishû = bring them to us5)

I'm doing this from memory, so if you have any more questions about word order, just say.

I leave you with this little gem:
Latu ghashnut narsrinkhshârzusharzuradu6).
sharz = very, if it isn't in the dictionary.

Translate that sentence and you are a master at suffixes. :D”

Author's notes

I don't agree with all that The Seconds Nazgul says, so here is my notes:

1) fulugugaz = fulug + gaz (house + small). One u was added for better pronunciation. But why not to shorten it to fulug(g)az or to spell this as two separated words?
2) Hey, u is not a suffix here! It's just a preposition meaning “to”! But this rule may be useful for non-English speakers. Another interesting detail: to Scatha shall be translated as “Scathau” or “Scatha-u”, but then we get diphtong, which isn't very good. Therefore she inserted z.
3) Isn't “thrakul nazgu” (without one u) clear enough to understand? I think it is.
4) Now I can agree. But not the best example is given. Here is mine: “Give the orcs an elf for sacrifice” = “Thrak golug urûku flîûr”. Without a suffix it will be almost impossible to understand, what and for whom shall we give. However in English we know what was meaned because of word order and articles. By the way, we can just change our phrase to “Give an elf for sacrificing by the orcs” = “Thrak golug flîûr urûkirzi” to solve all problems.
5) Once again, -u is a preposition here! But the essence of this rule is that the second pronoun is spelled separately from the verb, even if it's first person pronoun!
6) -ut in ghashnut is third person plural suffix, but we have Latu = you, 2nd person plural pronoun. I don't understand what this plenty of -u suffixes means here. Plural form of adverbs? Is it possible? One of them is definetely for pronunciations purposes, but what about the least of them? My variant is:
Latu ghashn narsrinkhshârzusharz(u)rad You are saying very nonunderstandably now

So, in my opinion, suffix -u shall be added in the third rule only or maybe sometimes in the 1st and the 4th rules!

Another bad thing with these rules is the overusing the suffix -u which already means both plural and preposition “to”.