Diphthong

In phonetics, a diphthong (also gliding vowel) (from Greek δίφθογγος, "diphthongos", literally "with two sounds" or "with two tones") is a contour vowel—that is, a unitary vowel that changes quality during its pronunciation, or "glides", with a smooth movement of the tongue from one articulation to another, as in the English words eye, boy, and cow. This contrasts with "pure" vowels, or monophthongs, where the tongue is held still, as in the English word papa.

Diphthongs often form when separate vowels are run together in rapid speech. However, there are also unitary diphthongs, as in the English examples above, which are heard by listeners as single vowel sounds (phonemes).

The fundamental unit of grammar is a morpheme. A basic unit of written language is a grapheme. And the basic unit of sound is a phoneme. However, this is technically what Professor Crystal describes as “the smallest contrastive unit” and it is highly useful to you in explaining things - but strictly speaking may not exist in real spoken language use. That is, almost anything you say is a continuum and you rarely assemble a series of discrete sounds into a connected whole. (It is possible to do this with synthesised speech, as used by Professor Stephen Hawking - but the result is so different from naturally occurring speech that we can recognize it instantly.) And there is no perfect or single right way to say anything - which is just as well, because we can never exactly reproduce a previous performance.

The physics and physiology of speech

Man is distinguished from the other primates by having the apparatus to make the sounds of speech. Of course most of us learn to speak without ever knowing much about these organs, save in a vague and general sense - so that we know how a cold or sore throat alters our own performance. Language scientists have a very detailed understanding of how the human body produces the sounds of speech. Leaving to one side the vast subject of how we choose particular utterances and identify the sounds we need, we can think rather simply of how we use our lungs to breathe out air, produce vibrations in the larynx and then use our tongue, teeth and lips to modify the sounds. The diagram below shows some of the more important speech organs.

This kind of diagram helps us to understand what we observe in others but is less useful in understanding our own speech. Scientists can now place small cameras into the mouths of experimental subjects, and observe some of the physical movements that accompany speech. But most of us move our vocal organs by reflexes or a sense of the sound we want to produce, and are not likely to benefit from watching movement in the vocal fold.
The diagram is a simplified cross-section through the human head - which we could not see in reality in a living speaker, though a simulation might be instructive. But we do observe some external signs of speech sounds apart from what we hear

Affixes

Types of affixes

Affixes are divided into several types, depending on their position with reference to the root:

Prefixes (attached before another morpheme)

Suffixes (attached after another morpheme)

Infixes (inserted within another morpheme) -- very much used in Borneo-Philippines languages
Circumfixes (attached before and after another morpheme or set of morphemes)

Interfixes (semantically empty linking elements in compounds)

Suprafixes (also superfix, attached suprasegmentally to another morpheme)

Simulfixes (also transfix or root-and-pattern morphology, discontinuous affix interwoven throughout a discontinuous base)

Duplifix (little used term referring to affix composed of both a reduplicated and non-reduplicated element, see Reduplication and other processes)

Affixes are bound morphemes by definition. Prefixes and suffixes may be separable affixes.

There also has been a proposal of a somewhat different type of affix, a disfix or subtractive morpheme, which subtracts phonological segments from bases.

syntax

In linguistics, syntax (from Ancient Greek συν- syn-, “together”, and τάξις táxis, “arrangement”) is the study of the rules that govern the structure of sentences, and which determine their relative grammaticality. The term syntax can also be used to refer to these rules themselves, as in “the syntax of a language”. Modern research in syntax attempts to describe languages in terms of such rules, and, for many practitioners, to find general rules that apply to all languages. Since the field of syntax attempts to explain grammaticality judgments, and not provide them, it is unconcerned with linguistic prescription.