Why the same name has many spellings
The lack of one-to-one mapping between Arabic and Latin scripts.
"Mohammed," "Mohamed," "Muhammad," "Mohammad," "Mahomet" — five spellings, one Arabic name (محمّد). The variants are not errors; they reflect choices about how to render Arabic sounds, with no single authoritative answer. The same problem affects Aisha / Ayesha / Aicha, Yousef / Yusuf / Youssef / Joseph, Khaled / Khalid, Ali / Aly, Gamal / Jamal, and many more.
Several distinct issues drive this variation. Each is a real linguistic problem; none has a clean solution.
Vowel choices
Arabic short vowels are often not written. The name written محمّد in Arabic script has no short vowels marked in ordinary writing — the letters represent only the consonants m-H-m-m-d (with the doubled middle m indicated by a small mark called shadda). The vowel pattern u-a-a-a is supplied from knowing how the name is pronounced.
In transliteration, those vowels have to be written explicitly, and there is no agreement on how. The first vowel in Muhammad is a short u — but is that closer to English "u" (Muhammad), "o" (Mohammad), or something between? Different countries and traditions made different choices.
Egyptian colonial-era English transliteration tended toward "Mohamed" — one m, with the colloquial Egyptian short vowel that sounds like "o" to English ears. North African and French-mediated transliteration gives "Mohamed" or "Mohammed" with French vowel sensibilities. Pakistani / Indian transliteration often uses "Muhammad" with American-style English vowels. Saudi documents use "Mohammed" or "Mohammad."
None of these is more correct than the others. They are all attempts to spell the same Arabic word for English readers.
Long vowels
Arabic distinguishes long and short vowels phonemically. The long vowel uu (a held u) in the name Yusuf can be transliterated as "u" (Yusuf), "ou" (Youssef, French-influenced), "oo" (Yoosuf, rarer), or even as just "o" if the writer was approximating the sound rather than the structure.
The same name in different languages: Yusuf (Turkish, Indonesian), Yousef (Egyptian English), Youssef (Lebanese / French-influenced), Yusup (some Central Asian transliterations), Yossef (occasional). All represent يوسف.
The ʿayn problem
Arabic has a consonant — ʿayn ع — with no English equivalent. It is a voiced pharyngeal fricative, produced deep in the throat. English has nothing close.
In careful academic transliteration, ʿayn is represented by an opening single quote, like ʿAli. In popular transliteration it is typically dropped entirely, leaving "Ali." In some French-influenced traditions it appears as aa or with a special mark.
The name Ali علي begins with ʿayn. The name Aly with a y ending is sometimes used by people whose family preserves a particular spelling preference. Saeed / Said have a ʿayn in the middle (سعيد); the spelling Saeed uses e to mark the consonant somehow, while Said just drops it.
The qaf problem
Arabic has both k (ك) and q (ق) as distinct sounds. q is a uvular stop, produced further back in the mouth than English k. English speakers do not distinguish them, and most ears cannot tell the two sounds apart.
In transliteration, q is sometimes written "q" (Tariq, Qais), sometimes "k" (Tarek, Kais), and sometimes the letter is silently merged with the standard k. The Levantine and Egyptian dialects often pronounce q as a glottal stop (so qaT becomes 'aT) or as g (Egyptian colloquial), leading to spellings like Tarek that reflect dialectal pronunciation rather than the underlying classical sound.
The jim problem
The Arabic letter jim ج is pronounced differently in different dialects. In MSA and most dialects (Levantine, Gulf, Iraqi, North African with variation, Sudanese) it is a "j" sound — close to English j. In Egyptian Arabic it is a hard g — like English g in "go."
So the name Jamal جمال is "Jamal" in most contexts, but Egyptian Gamal Abdel Nasser is universally written "Gamal" — because that is how Egyptians pronounce his name. The name "Jaber" can be Gaber (Egyptian) or Jaber (other dialects). Egyptian English-language documents preserve the g, while almost everyone else uses j for the same letter.
The ta-marbuta problem
Arabic has a special letter at the end of feminine words, taa' marbuuTa ة. It is pronounced "a" most of the time but can be pronounced "at" in formal contexts (in iDaafa constructions). The spelling reflects this dual nature.
So the name Fatima فاطمة can be transliterated as Fatima (the everyday pronunciation), Fatimah (with an h to mark the unsaid t), or Fatimat (the formal Quranic pronunciation in compound forms). Aisha appears as Aisha or Aishah; Khadija as Khadija or Khadijah. Older British transliteration used the h-form; modern American usage often drops it.
Country conventions
Different countries developed different conventions. Egyptian English transliteration was shaped by British colonial administration and reflects Egyptian pronunciation: Gamal, Mohamed (one m), Hosny, Saeed. French colonial Maghreb transliteration used French vowel rules: Mohammed, Aïcha, Youssef, Mehdi. Saudi government transliteration tends toward the conservative Anglo-Indian "Mohammad" / "Khalid" / "Abdullah." Lebanese and Syrian families often have French-influenced spellings.
Government documents, particularly passports, fix a spelling for an individual that may then propagate to all their children regardless of how those children would otherwise spell it. The result: a single family may have one spelling on the passports of older relatives and a different spelling for younger ones, all referring to the same Arabic name.
The hamza problem
The hamza ء is a glottal stop — the catch in your throat between the two syllables of "uh-oh." Arabic treats it as a consonant; English does not write it as a letter. In careful transliteration it appears as an apostrophe (Asma' for أسماء); in popular use, it is dropped, leading to spellings that mask its presence.
What this means for English speakers
Three practical takeaways.
First, do not assume a single "correct" spelling. If someone signs their name "Mohammed," that is their name. Do not spell it "Muhammad" because you read somewhere that's the canonical form. The bearer's choice is the correct spelling for their name.
Second, when searching for someone — a person, a historical figure, a family — try multiple spellings. A single Wikipedia page may exist under one transliteration but mention all three.
Third, recognize that academic transliterations (with diacritics, capitals for emphatics, ʿ for ʿayn) and personal-name transliterations (smooth English-looking spellings) serve different audiences. Both are useful; neither replaces the other.