Way back at the beginning of the semester, when talking about characteristics of all languages, we learned that language is hierarchically structured: That is, sentences are composed of groups of words. within those groups, you can see smaller groups. Within those groups' there are individual words. Within words, there are morphemes. and morphemes are made up of sounds. So let's start at the top:
Divide this sentence in half:
The big walrus with the yellow flower searches the forest for the hip young female of his dreams.
Probably, you made the division like this:
The big walrus with the yellow flower --- searches the forest for the hip young female of his dreams.
That first part of the sentence is the noun phrase. We could replace that all with one simple little 'he' (or it, if you prefer).
He searches the forest for the hip young female of his dreams.
The ability to replace all of that with one pronoun is a good test to tell you that it's a single, coherent whole: a phrase.
If you had to pick only one word, which word is the most important word of this phrase?
The big walrus with the yellow flower
You probably picked Walrus.
As it happens, Walrus is a noun. this phrase is a noun phrase. Phrases are named after the most important word in them. That word is called the head of the phrase.
In the noun phrase in this sentence, there is a head (walrus) and there is other material that goes with (modifies) the head. the adjective 'big' and the prepositional phrase 'with the yellow flower' all describe the walrus.
Language typologists are linguists who look for patterns across languages. they want to see what is normal and usual in languages of the world and what is odd. It is from typologists that we get the kind of information you used in step two about what segments are common in the languages of the world ( [t] and [a] for example) and what sounds are more rarely found (clicks for example).
Typologists also look for patterns in the syntax of languages. One pattern they tend to find is that languages tend to be either head-first or head-final. Understand that this is a generalization across a huge amount of data and your mileage may vary. But here's the essence of the finding:
Within a particular language, heads of phrases (that is the noun in a noun phrase, the preposition in a prepositional phrase, the verb in a verb phrase) tend to come either all first or all last with respect to other words in that phrase.
Japanese is a terrific example of a language that is consistent in this regard. (The SUBJ and OBJ markers below are indicators of the subject and object of the sentence respectively).
In this example, we can see:
Thus, Japanese is a very consistently head-final language.
Spanish is an example of the opposite.. watch how all the heads come first.
In this example, we can see:
Spanish is a very consistently head-initial language.
However, In English we have:
Thus, English is sort of a mixed bag. It does turn out the SVO languages (that is, languages that place a subject first, then a verb, then an object as we have done in this sentence) tend to vary in terms of noun adjective order. It's not just English being difficult.
But, if you were summarizing this, you could say that English is a mixed case but has more head-initial than head-final phrases.
A little summary: