5.2 Motivation
Motivation(理据) refers to the connection between the linguistic symbol and its meaning. As we know, the relationship between the word-form and meaning is conventional and arbitrary, most words can be said to be non-motivated(没有理据的). That is, the connection of the sign and meaning does not account for the meaning. Nevertheless, English does have words the meanings of which are transparent(透明的,清楚的;意义与形式有联系的) and reasonably explicable(可解释的).
1. Onomatopoeic Motivation(拟声理据)
In modern English one may find some words whose phonetic forms suggest their meanings as the words were created by imitating(模拟) the natural sounds or noises. For example, bow-wow, bang, ping-pong, miaow, cuckoo, tick-tuck, ha ha and the like are onomatopoetically motivated words. Knowing the sounds which they represent means understanding the meaning. All the words based on the sounds made by birds, animals, insects and so on belong to this category: crow by cocks, quack by ducks, trumpet by elephants, buzz by bees or flies, croak by frogs, squeak by mice, neigh by horses, bleat by goats, hiss by snakes, roar by lions, etc. . But such echoic(拟声的;回声的) words are conventional to quite a large extent, for the sounds we say in English may not be the same in other languages; splash and whisper do not mean 'splash' and 'whisper' for example in German or French (Quirk 1978).
2. Morphological Motivation(形态理据)
Compounds and derived words are multi-morphemic(多词素的) words and the meanings of many of them are the sum total of the morphemes combined. Often, when one knows the meanings of the morphemes or bases, one can deduce the meanings of the words. For instance, airmail means ' to mail by air' ; reading-lamp is ' the lamp for reading'; miniskirt is 'a small skirt'; and hopeful means 'full of hope'.
It should be pointed out that there are a lot of words whose structures are opaque(不透明的,不发亮的;难以理解), i.e. their meanings are not the combinations of the constituent parts. Black market, for example, is by no means the market black in color but expressing 'illegal selling and buying'. Likewise, egghead is not the head in the shape of an egg, but ' a learned person' in the derogatory(毁损的,贬低的) sense.
3. Semantic Motivation
Semantic motivation is the mental associations based on the conceptual meaning of a word. In other words, it is the figurative(比喻性的)sense of the word. When we say the mouth of a river, we associate ' the opening part of the river' with ' the mouth of a human being or an animal'. When we use the foot of the mountain , we are comparing ' the lower part of the mountain' to ' the foot of a human being'. Bottle in ' He is fond of the bottle' reminds one of what is contained inside; and pen and sword in ' The pen is mightier(更强大的) than the sword' is suggestive(示意的;启发的;引起联想的) of 'writing' and 'war'.
4. Etymological Motivation
The origins of words more often than not throw light on(说明,揭示) their meanings. For example, now people use pen for any writing tool though it originally refers to 'a heavy quill(羽毛管;羽根) or feather', because before modern pens were created, feathers were trimmed(整理;修剪) to a split point(有分叉的尖端), used as writing tools. Though people in modern times no longer use feathers in writing, for the sake of conventionality, the name is retained. All the words commonized from proper names can be explained in terms of their origins. One example will suffice(足够) for illustration. The word laconic meaning 'brief' or 'short' is derived From Lacons, a tribe of people who were known for their brevity(简洁;简练) of speech and for their habit of never using more words than necessary. Hence a Laconic answer is 'a short answer' (See Commonization of Proper Names for details).

