Aspirates

Aspirated consonants are consonants whose pronunciation ends with a puff of air, like a short h sound. Proto-Indo European had aspirated consonants, which are denoted with a superscripted h: b^h, d^h, g^h, ǵ^h, g^ṷh (the latter two symbols stand for the aspirated and ).

Cases

Cases are the different forms a noun, adjective or pronoun can take to indicate its role in a sentence. For instance English he can function as a subject, but him is the form for the object in "he saw him". is thought to have had 8 cases, like Sanskrit:

• Nominative: marking the subject (John is tall)
• Accusative: marking the direct object (John hit Bill)
• Genitive: marking possession (John's dog)
• Dative: marking the indirect object (John gave the dog to Bill)
• Ablative: marking the point of origin (John came home from work)
• Instrumental: marking the instrument (John hit the nail with a hammer)
• Locative: marking location (John is at home)
• Vocative: marking direct address (hey John!)

A Proto Indo-European sentence featuring all the cases might have looked something like this (however very little is known about word order):

voc		nom	dat	acc	loc	inst	gen	abl	(verb)
póti	,	méh2tr	ph2tréi	gṷéh3um	h2éǵroi	iugóh1	bhrh2trós	ulkṷōd	uéǵhe
master		mother	for father	bull	in the field	with yoke	of brother	away from wolf	leads
Master! Mother is leading the bull in brother's field for father with the yoke, away from the wolf.

Centum and Satem Languages

Centum languages (pronounced "kentum") are Indo-European languages in which merged with regular velars (this process may be called centumization). In satem languages the merged with regular velars (satemization). The names for the two groups come from the pronunciation of the word for "hundred" (which started with a palatovelar) in Latin (a centum language) and Avestan (a satem language).

Labiovelars

Labiovelar consonants are velar consonants (pronouned with the tongue touching the velum, like k, g) whose pronunciation ends with a labial w element. The English word 'queen' begins with a labiovelar. had three labiovelars, which are denoted with a superscripted u: k^ṷ, g^ṷ, g^ṷh (the latter symbol stands for the labiovelar).

Laryngeals

Laryngeals are sounds produced in the larynx, lower in the throat than other sounds. The glottal stop before an initial vowel in English is a laryngeal, e.g. the first sound before the u vowel in the word up. is thought to have had three laryngeals, marked h₁, h₂ and h₃ (their exact pronunciation is unknown). In certain environments it cannot be determined which laryngeal was present, in which case we write a capital H.

Palatovelars

Palatovelar consonants are velar consonants (pronouned with the tongue touching the velum, like k, g) that are pronounced with the tongue towards the palate (somewhat like the k in "kid" as opposed to the c in "cone"). had three palatovelars, which are denoted here with an accute sign on top: ḱ, ǵ, ǵ^h (the latter symbol stands for the palatovelar). See also .

Proto Indo-European

Proto Indo-European (PIE) is the name given to a hypothetical prehistoric language, which would have been the ancestor of all known Indo-European languages. Historical linguists try to reconstruct PIE word forms (or proto forms) by comparing related words in different languages and positing a common ancestor form from which the attested forms can best be explained. These proto forms are usually marked with a star (e.g. *d^heh₁) to show that they are only postulated and not attested. While some think PIE was actually spoken at some time (perhaps in the 4th or 5th millenium BC), others are less sure such a uniform language ever existed, and prefer to regard proto-forms as useful abstractions which describe the relationships between related languages.

Reduplication

Reduplication is the repetition of part or all of a word form to produce a new word form, like 'bye bye' (which is not simply saying goodbye two separate times). In old Indo-European languages reduplication of part of a verbal stem played an important role in forming different tenses, e.g. Greek present dí-dō-mi 'I give' : aorist infinitive dó-menai 'to give', where the prefixed di- is reduplicating the begining of the stem do-.

Root

Almost all Indo-European words can be derived from a root. The root supplys the basic lexical meaning of all words derived from it, e.g. from the root build we get build-er, build-ing-s, build-s etc. roots had the following properties, which are still reflected in the modern languages:

1. They have only 1 syllable
2. The syllable can start with 1-2 consonants and end with 1-2 consonants.
3. Between these consonants is a vowel, usually e, which can however change into other vowels or disappear as a result of
   vowel gradation
   .
4. Roots cannot have a voiceless stop (p, t, k) and an
   aspirated
   consonant: *b^hek and *keb^h are impossible roots.
5. They cannot both start and end with a voiced stop (b, d, g): *bid, *geb etc. are impossible (in English such combinations have developed e.g. from aspirates bid < *b^hid^h-)
6. They have rising sonority up to the vowel, then falling (see below). The only exception to this is the possible addition of a prefix s- (see also
   s-mobile
   )

The basic structure is thus (s)(C)CeC(C), where C can be any consonant . Most apparent exceptions to these rules stem from a : Eng. is < *h₁es-, where the lareyngeal h₁ is a consonant. The last criterion (VI) means that as a root is pronounced, more and more air is released with each sound, up to a peak, after which less and less air is released. As we can see from the following two diagrams, the sequence strong would form a valid root, but strength would not:

o air s r n     t g   time

e   air s r n   th     t g   time

You can try pronouncing these words slowly, sound by sound, to see how more and less air gets released with each sound.

S-Mobile

The mobile s (or s-mobile) is a prefixed s- that appears in certain words, which also appear elsewhere without the s-, either in another language, or even in the same language. For instance, the two English words melt and smelt are very similar (the latter is restricted to melting metals etc.), and are most probably derived from the same root. Originally the s- must have had a separate meaning, which has been lost over time.

Stems and Suffixes

In Indo-European languages, a stem is the part of a word up to its inflectional ending. For instance, the word dogs has a stem dog- and an ending -s, which marks the plural. Stems themselves can be composed of and suffixes: the word meetings is comprised of a root meet-, a suffix -ing- which forms nouns from verbal roots, and finally the plural ending -s. In old Indo-European languages, we often classify stems according to the last sound of the last suffix (e.g. s-stem, n-stem), since this affected the inflection of the word. The distinction between stem types has been completely lost in English, except in a few irregular forms, such as ox : oxen, where the n-suffix of an old n-stem still appears in the plural.

Vowel Gradation (Ablaut)

Vowel gradation is the alternation of vowels in different forms from the same root, e.g. English run : ran shows a vowel gradation that distinguishes past and present forms of the same verb. had three vowel grades: the full-grade (with the vowel e or sometimes o, respectively also called e- and o-grade), the Ø-grade (with no vowel) and the lengthened grade (with long ē or ō). The alternation was at one time probably a result of the stress: stressed syllables had a vowel (usually -e-), but in unstressed syllables the vowel disappeared. The most common forms were those with the full e- and o-grades, and also the Ø-grade, which marked for instance forms in the present, the perfect and the participle respectively. We can still see the continuation of these grades (e : o : Ø) in irregular verbs in English:

	present (e)	perfect (o)	participle (Ø)
Proto-Stems	*-ghen-	*-ghon-	*-ghn-
English	(be-)gin	(be-)gan	(be-)gun

Since different grades appeared in various forms of the same word, different languages often generalized one of the grades to all forms of the same word (as an illustration of this idea, imagine what would happen if Americans would start saying "I have began" while say Australians would say "Last year I begun..."). This is why we sometimes find different forms stemming from different grades in related words in different languages.