Is Riley the same name as Ryleigh? What about Emily, Emmalee and Emilia? Ask any mom of a Riley or Emilia, and they'll tell you absolutely not. Small variations in a name can carry big cultural distinctions.
Those variations, by the thousands, are a defining feature of today's name landscape. They're hardly a new phenomenon, though. For a case study of fine -- but important -- name distinctions, let's turn to the most influential naming text around: the Bible.
Allow me to present two classic biblical names. Matityahu is Hebrew meaning "gift of God," with the Greek form Matthaios. Yehuda is Hebrew meaning "praised," with the Greek form Ioudas. Each of the names is borne by multiple biblical men, with three pairs of linked examples.
In the Books of the Maccabees (Bible in some traditions, apocrypha in others), the Jewish priest Matityahu rejects the assimilation demands of the Seleucid Greeks, sparking a war of revolt. One of Matityahu's sons, Yehuda, becomes the leader of the revolt and is one of the Bible's legendary warriors. You may recognize the father-son pair better as Mattathias and Judah Maccabee.
In the Gospels we find multiple accounts of how Jesus selects and trains 12 apostles to spread the good news and establish the church. Among the 12 are Matityahu, Yehuda and Yehuda. You probably know them as Matthew the Evangelist, Jude the Apostle, and Judas Iscariot.
Later, after Judas betrays Jesus, another apostle named Matityahu is chosen to take his place. You probably know him as Matthias the Apostle.
Names can vary among different versions of the Bible, and even from book to book within a single version. (Jude is referred to at times as Thaddeus, Matthew as Levi, etc.) I'll leave it to more qualified biblical scholars to explain how and when Mattathias/Matthew/Matthias and Judah/Jude/Judas diverged. But here's the kicker. It's widely accepted that the distinctions were deliberate choices on the part of translators, with the purpose of clarifying the text.
The translators took advantage of linguistic variations to carve out little arenas of name individuality. As a result, those variants have very different cultural connotations today. Naming a son Judah creates cultural and stylistic links to Judah Maccabee, the Lion of Judah, and the same kind of antique style that separates Jeremiah from Jeremy. Naming a son Jude suggests Jude the Apostle, St. Jude, Jude Law and "Hey Jude." Judas, meanwhile, has become a word meaning "traitor."
The same process happens, albeit on a less dramatic level, with most modern name variations. Ryleigh doesn't summon the same Irish androgyny as Riley. Only Emily connects to the likes of Dickinson, Bronte and Post. If you accept that a name's "meaning" goes beyond its derivation, then the meaning shifts with every variation.