Further terms are explained in Linguistics Glossary

agreement: the grammatical system in which two elements in the sentence show they go together through linked word inflections etc, for example singular verb and singular subject in the English present tense, he goes/they go, feminine and masculine gender John/he,/ Mary/she etc.

animacy: whether a noun is animate ‘fox’ or inanimate ‘rock’. Not particularly important in English but vital for forming subjects of sentence in Japanese, Italian etc, which have to be animate

articles: in English the specifiers of nouns are divided into definite articles ‘the man in the photo’, indefinite articles ‘a man came in’ and zero article Ø (i.e. none) ‘Man is mortal’. In other languages like French they have to agree with the noun in gender.

case: a grammatical system in many languages in which words show their grammatical function (Subject, Object etc) by having different forms. In English, surface case only affects pronouns (‘I’, ‘me’, ‘my’ etc) but case is still invisibly important. 

content and structure words is a way of classifying words popular in teachers’ grammar since at least the 1950s, which distinguishes content/lexical words that belong in dictionaries, like nouns ‘tennis’ and verbs ‘open’, from structure/function words that need to be explained in grammar rules like ‘from’ and ‘who’.

gender: in grammar, gender is a relationship in which some words in the sentence ‘agree’ with one another. In languages like English, pronouns have to agree with their linked nouns in terms of whether they refer to things that are masculine or feminine – ‘John … he, his, him’, ‘Jane … her, hers’ etc, ; this is called natural gender as it refers to the object’s actual sex. In some other languages pronouns, articles, adjectives etc agree with the nouns that are masculine or feminine grammatically, ‘Das Mädchen’ (German, ‘the girl’, neuter), ‘La table’ (French, ‘the girl’, feminine), ‘Il ristorante’ (Italian, ‘the restaurant’, masculine). This is called ‘arbitrary’ gender since it links to word-classes called masculine and feminine, not to the object’s actual sex.

grammar is the system of relationships between elements of the sentence that links the ‘sounds’ to the ‘meanings’, by means of word order, word forms, etc (a Chomskyan style definition): ‘the grammar is seen as a network of interrelated meaningful choices’ (a Hallidayan definition). However the term ‘grammar’ is dangerous as it is used in many different ways.

grammatical morphemes is a term in SLA research for morphemes such as ‘-ing’ and ‘the’ that play a greater part in the structure of the sentence than content words such as ‘horse’ (lexical morphemes).

inflections are a grammatical system for showing meaning by changing the form of words through adding morphemes. The singular noun ‘map’ becomes the plural ‘maps’ by adding the inflection ‘s’, the present tense ‘walk’ becomes the past tense ‘walked’ by adding ‘ed’, and so on. Inflections are not very extensive in English, vital in Latin, and non-existent in Chinese.

morpheme: the smallest meaningful unit of grammatical structure, consisting either of a word (‘toast’) or part of a word (‘’s’ in ‘John’s’). Morphemes are either ‘free’ in that that they can occur as independent words, like ‘good’, ‘fight’ or ‘vote’ or ‘bound’ in that they have to be attached to something else, ‘-er’ ‘reporter, ‘in-’ ‘independent’, ‘-ly’ ‘hopefully’, etc. Discussion of different ways of forming words can be found at http://homepage.ntlworld.com/vivian.c/Words/index.htm.)

morphology and syntax: grammar is often divided into syntax (above the word) and morphology (below the word).

morphosyntax: some SLA researchers now prefer this term to grammar. This is at odds with linguists who reserve morphosyntax for the small overlap of  syntax and morphology, not as an inclusive term for both.

movement is a way of describing the structure of the sentence as if elements in it moved around, typically  English questions and passive constructions (i.e. it does not mean they literally move, though this may be implied in the mental process used in Processability Theory). This is illustrated in Fig 2.3.Thus the question ‘Will John go?’ comes from a similar structure to that underlying the statement ‘John will come’ by movement of ‘will’. 

number is a way of signalling how many are involved, for example through the inflected forms of nouns, pronouns and verbs, ‘book/books, he/they, swims/swim’. English has two numbers, singular (‘he’) and plural (‘they’). Other languages do not have grammatical number (Japanese), or have three numbers (Old English), and so on.

parameters: in post 1981 Chomskyan syntax systematic differences between languages are captured by setting the value for a small number of parameters, like a row of light switches each set to on or off, such as the pro-drop parameter

passive and active voice expresses similar meanings to active sentences but shift the focus from the agent doing the object to the object enduring the action by movement ‘I broke the mirror’/‘The mirror was broken’.

past tense: in English this is usually formed by adding ‘ed’, in speech taking three forms /t/ walked, /d/ played and /id/ waited, with many irregular forms like ‘said’, ‘ran’, ‘hit’ etc. A comparison of the different rules for spoken and written English is given in http://homepage.ntlworld.com/vivian.c/Writings/Papers/PastTense03.htm

phrase structure grammar links all the parts of a sentence together in a structure like that of a family tree by splitting the sentence into smaller and smaller bits, as seen on Fig 2.1. This was formalised by Chomsky in 1957, who pointed out its inadequacy as a theory of grammar, particularly for handling discontinuous elements, like ‘will’ and ‘be’ in ‘Will you be late?’.

prepositions are words like ‘to’, ‘by’ and ‘with’ which come before nouns in English to make Preposition Phrases ‘to London by plane with Easyjet’. When they follow the noun, as in Japanese, they are called ‘postpositions’ ‘Nippon ni’(Japan in).

principles of language: in the Universal Grammar theory, the human mind has a small set of abstract built-in principles of language that permit or prohibit certain structures from occurring in all human languages which are thus never broken in human languages, though some human languages may not need them. For example languages in which questions are not formed by syntactic movement do did need principles of movement.

pro-drop parameter (null subject parameter): in pro-drop languages the surface Subject of the sentence may be left out, as in Italian ‘Sono di Torino’ (am from Turin) and Chinese ‘Shuo’ (speak), in non-pro-drop languages such as English, German and French the Subject must be present in the actual sentence.

progressive (continuous) aspect: in English this consists of an inflection ‘-ing’ added to the verb and the appropriate form of ‘be’: ‘I am paddling’, ‘Peter is sailing’, ‘Penny and June are swimming’ etc but is not used for ‘private’ verbs like ‘think’ except in some regional varieties, ‘I am thinking’.

pronouns such as ‘he’ and ‘them’ differ from nouns in that they refer to different things on different occasions: ‘She likes it’ can refer to any female being liking anything; ‘Helen likes Coltrane’ only to a specific person liking a specific object. English pronouns have case for gender (‘she’ versus ‘her’) and number (‘she’ versus ‘they’).

questions: many languages make a difference between questions that demand a yes/no answer; ‘Can you drive a lorry?’, formed by word order, and questions that are open-ended ‘What can you drive?’, which involve movement and an initial question-word such as ‘why’ or ‘who’. The latter are called question- word questions or wh-questions in English because question-words mostly happen to start with ‘wh’, like ‘when’ and ‘who’.

Subject can be defined in many ways. In one it is the Noun Phrase of the sentence alongside the Verb Phrase in its phrase structure, i.e. ‘(The man) (fed the dog)’ in Fig 2.1. Subjects are compulsory in non-pro-drop languages in the actual sentence (though present beneath the surface) but may be omitted in pro-drop languages like Italian; it often acts as the ‘agent of the action’ in English and agrees in number with the verb.

word order: for many languages the order of the main elements in the sentence is crucial, whether Subject (S) Verb (V) Object (O), as in English ‘People love pizza’, SOV in Japanese, VSO in Arabic, or whatever. Other word order variations are whether the language has Prepositions before the Noun Phrase ‘in New Orleans’or postpositions after the Noun Phrase ‘Nippon ni’ (Japan in) and whether questions or subordinate clauses have distinctive word orders.