A bit of darling etymology
Last night, as we were sitting at the dining room table, my roommate suddenly wanted to know the history and original meaning of the word "darling." (She's a curious person by nature. Happily, I like doing research and I'm good at it, so we're a good team.) So I pulled up The American Heritage Dictionary of the English Language and discovered that it comes from Old English "deorling," which is comprised of "deore" ("dear") = "-ling" (a diminutive suffix).
A "suffix" is a word part which attaches to the end of a root word to change its meaning. (If it attaches to the beginning of the word, it's called a "prefix." The general term for all such words parts is "affix.") Suffixes usually can't stand along as a separate word, although they do carry meaning. Other suffixes include "-s" (which changes a singular noun into a plural noun), "-ing" (which changes a verb into its present participle), and "-er" (which changes verb "X" into a noun meaning "one who does X").
So "-ling" is a diminutive suffix, which means that it attaches to the end of a root word and changes the meaning of the word from "X" to "little X." I.e., "Darling" means not just "dear" but "small and dear."
I was curious to know what other modern English words included the suffix "-ling," so I fired up the OED online to do an advanced search on all entries which include "ling" as part of the etymology.
Many of the words I found were comprehensible in meaning, but simply not used by modern English speakers (cheeseling, doveling, authorling). Of the words we still use, a surprising number had to do with animals (duckling, fledgeling, gosling, hatchling), but not all (changeling, earthling). I found some words that I hadn't realized followed the (root + "-ling") pattern, because I didn't understand the root. These include:
dumpling (in this case "dump" may refer to a mass of something moist and heavy, such as dough)
sibling ("sib" being an Old English word meaning "kinship")
starling ("stare"/"stær" referred to any bird of the genus Sturnus, whereas "starling" referred to Sturnus vulgaris)
Suffixes can be either "productive" or "unproductive." Productive suffixes are still being used to make new words. Unproductive suffixes existed in an earlier form of the language and may still exist in some old words, but we're not making new words with them any more. "-er" is a productive suffix, as evidenced by the word "blogger." "Blog" isn't a very old word at all, so "blogger" must be even newer, but its meaning is instantly comprehensible to English speakers.
"-en" is an unproductive suffix. (It's so unproductive, that you might not even know what it means.) It's a pluralizing suffix, as in the words "oxen," "children" and "brethren." However, it has long since been replaced by "-s" as the current pluralizing suffix, so people wouldn't even know what you meant if you said "blogen," and the words which still contain it as a suffix are just learned individually as irregular plurals.
So, is "-ling" a productive suffix? There are some OED "-ling" entries which date from the 20th century, although they're not very common words. (In my vocabulary, at least. You may happen to use "sporeling," "waspling," or sharkling" on a more regular basis.) That said, I think someone would still get the general gist if you said "blogling," which probably wouldn't be the case with "blogen." I guess we'll call it "mostly unproductive."