Take for example the name SANDERS.
Sanders is a patronymic surname derived from the given name "Sander," a medieval form of "Alexander." Alexander comes from the Greek name "Alexandros," meaning "defender of men" from Greek alexein "to defend, help" and aner "man." source: about.com
SANDERS ranks as the 87th most popular name in the USA; the most popular surname is SMITH, followed by JOHNSON, according to the census of 2000.
To find the meaning of your name, there are several sources such as: about.com, ancestry.com.
Name spellings also change due to misspellings, but also because we migrate to other areas or the culture around us changes, over time.
Take for example the words I used in the title: "The Phrenetic Phonetic Phoenician Nose". If I was from a region in the mid-west, USA, and just spoke those words to you, then you might believe I was talking about a frantic ancient Mediterranean person whose profession might have something to do with words.
However, with the written expression, its is clear I am referring to a "nose" rather than a learned professional who "knows". By the way, the word Phoenician also describes a person who lives in Phoenix, Arizona.
With this in mind, I can now interpret this as a Phoenix Arizonan NOSE that can spout off words really frantically.
So what does this have to do with name meaning and spelling? Everything!
When doing research about a family name, going back further in time, be sure to know the context of the sources because people migrate, cultures change. Sometimes this can help you get through your road block, by stepping back and thinking like a local.
All comments welcome... suggestions to the contrary are respected and expected.