A mnemonic is just a memory aid – an artificial way of remembering information that would be difficult to memorize otherwise. For example, if you hold up your two hands with thumbs outstretched, you might be able to see an “L” on the left – this is a way of unambiguously distinguishing between left and right.
Their use in language learning has always been somewhat contentious, and there have been raging arguments on both sides; certainly in schools, their usage has been somewhat limited. At one point, I was convinced that memory-aids were the be all and end all to language learning; however, after a heated discussion on the RevTK forums, I changed my stance.
My current outlook is this – in cases where there is interference in something that’s being learned, for whatever reason, then a mnemonic is a good way of accurately distinguishing between the two (interference is where the creation of one memory makes it harder to recall another).
I used mnemonics extensively when I started out on Cantonese, for perhaps the first two or three hundred words. When you’re first starting out on a language, it can be difficult to remember words because you’re dealing with new sounds, new writing systems and so on – memories of these words tend to be subject to a lot of interference.
Thereafter however, becoming more familiar with the language, it became easier and easier to learn new words – the same consonant and vowel sounds kept appearing, and patterns in the pronunciations of Chinese characters became apparent. I therefore swapped to a faster method of vocab acquisition (i.e. by rote), and I’m mostly using that at the moment.
That’s not to say I don’t use mnemonics at all – words still interfere sometimes and I’ve then got no choice but to come up with a way of distinguishing between them. In fact, quite recently I found that I could no longer recall the pronunciation of 替代 (tai doi, replace), so I came up with a memory aid – tie a doily up to replace a ping-pong ball. Ridiculous, but I haven’t forgotten it since.
However, I’ve found that mnemonics at this stage are unwieldy – whereas it takes on average perhaps ten to fifteen seconds to learn a new word by rote (and no time if learned incidentally), I find it takes twice that to come up with a mnemonic – the above took 30-40 seconds because the sound “doi” isn’t very common in English. It also takes longer to piece together whatever the word was from the mnemonic. For the most part, they just aren’t time-efficient, which can be frustrating – the faster you build vocab, the faster you reach fluency.
Anyway, those are just my thoughts – I was interested to hear Benny the Irish polyglot say that he uses mnemonics a lot to bulk up his vocabulary; Nathan Cain also uses them a lot for Mandarin study. Conversely, Khatzumoto has said that he’s looking at ways of ditching mnemonics for remembering kanji as they involve a lot of extra work. I’m curious to know what the general consensus on their use is – are they a lifesaver, a timewaster, or a little bit of both?