This is a terrible, massively inaccurate book. It is filled with misinformation and egregious errors. These are not simple typos, they are serious problems that will greatly misinform the reader at every turn. There are not just a few errors, there are more than one hundred! The more I look, the more errors I find -- multiple errors per page! I wish I could change my vote to ONE STAR.
If you buy this book for yourself or another person, you will only spread misinformation.
This book does not include anything from The History of Middle-Earth, but that is not a severe problem, since including all of that would require several volumes.
The chapters on Hobbit, Dwarven, and Rohirric names seem fine.
But the sections about Elvish languages and the dictionary contain an unacceptable number of serious errors, misspelled words, and wrong information. How can you learn to speak Elvish from a book where the words are spelled wrong? Here is a list of [some of] the errors that I found.
1. Consonant mutation, an essential part of Sindarin grammar, is totally ignored. You just can NOT learn or use Sindarin without the consonant mutation.
In the Glossary and Dictionary:
2. Several words and names are assigned to the wrong language (including aiya, Altariello, Andúni, Aros, Baran, Bereg, Carn Dm, Golfimbul, kal, khelek, le, Morgoth, oial, omentielvo, Shagrat, Sindarin, tark*, tarkil, Turgon). Many of these were correctly identified in the Quotations Translated chapter, while others are identified in the Silmarillion or Lord of the Rings, so this is clearly a case of sloppy editing.
*an Orkish word, listed under Quenya!
3. In the Dictionary, Noel lists "Hobbit" as a language separate from Common Westron. This is plainly untrue, Noel herself agrees that the Hobbits spoke Westron. There is no such language as "Hobbit." All of the words identified as "Hobbit" in the Dictionary are actually Common Speech (Westron).
4. Many words and names are spelled wrong (including "ae" and "ai" for aeg; "Dearon" for Daeron; "faelivren" for Faelivrin; "galadrim" and "gladrim" for Galadhrim; "gelyd" for Gelydh; "chil" for hl; "ivren" for Ivrin; "luine" for luini; "blung" for lung; "ma" for mab; "mard" for mard; "nalda" for nalla; "ro" for roh/roch; "singe" for singi; "dil" for til; "dir" for tir; "diriel" for tíriel; "utuv-" for tuv-; "val" for Vala). Some of these happened when Noel completely ignored grammatical consonant mutation, which is very important in Sindarin grammar. Several other words are written and spelled correctly in another chapter, so this is another case of bad editing.
5. Some words are translated wrong, even though Tolkien had provided a translation which the author includes in the Quotations Translated chapter! (including aeg, ambar-metta, oial, le, oio, tathren, ú-chebin, wen)
6. The author includes her own translations and etymologies for many names, and gets a HUGE number of them wrong (including Amlach, Amras, Amrod, Aranw, Baran, Boromir, Boron, Caranthir, Caras Galadon, Carn Dm, Carnil, Celegorm, Curufin, Curufinw, Denethor, Dorlas, Edrahil, Elenion, Elenw, Elu, Elw, Endorenna, Ered Lindon, Finarfin, Finarphir, Fingolfin, Finw, Forlindon, Glingal, Guilin, Haldan, Haldir, Halmir, Handir, Harlindon, Helcarax, Illuin, Ilmar, Ilmarin, Imlach, Ioreth, Lindon, Lindóri, Lórellin, Lórien (Q), Lothlórien, Luinil, Lúthien, Maedhros, Maglor, Malach, Mandos, Míriel (Q), Nerdanel, Ringil, Rómenna, Silpion, Tarondor, Tr Haretha, Valacar). Some of these errors were not apparent before Peoples of Middle-Earth was published, but most of them are not excusable in this way. Sometimes the author ignored the correct translation written in the Silmarillion. Given the paucity of information available in the sources used, Ruth Noel should not have published these baseless, hypothetical translations.
7. Suffixes and roots are listed as words, with nothing to distinguish them (including alak, ma, mbar, ndak, uva). This is especially a problem in the Glossary.
8. King Anárion is identified as the son of Eärendil! I have no idea where this came from. Anárion was in fact the son of Elendil.
Other parts of the book are deeply flawed as well:
9. In Quotations Translated, one of the quotes is misidentified as the wrong language ("A laita te.."). This quote is actually Quenya.
10. In the English-to-Elvish Glossary and the Dictionary, the author does not identify the language for most of the words and names, making these sections, especially the English-to-Elvish Glossary, almost useless. Noel claims that most Elvish words cannot be identified as one language or another, but this is completely false. Sindarin and Quenya are especially easy to tell apart. She also says that Proto-Quenya words are identified by an additional note, but none of them are.
11. In the Glossary and Dictionary, and in the Using Elvish chapter, hypothetical and reconstructed forms are ~never~ distinguished from real (attested) words. This is a serious problem in a linguistic work, and doubly so when working with copywrited constructed-languages.
12. There is inconsistent use of diacritics, which are important to the spelling of Elvish, Adnaic, and Dwarven words.
These are not simply mistakes, and there are more than one hundred of them. They display a complete lack of editing. Considering the small size and limited scope of this book, so many errors make the main portions of this book worse than useless. Especially now that much more information is available, both in The History of Middle-Earth and in other linguistic publications, you can easily find a book of similar scope that is both accurate and useful. I recommend that you visit Helge K. Fauskanger's excellent linguistic website Ardalambion, which is accurate and continually updated as more of Tolkien's linguistic texts are uncovered. Ardalambion also provides a list of further online resources.