seems to be best explained by supposing that the -u and -i are postpositions, a conclusion which is strengthened by the Greek rule that -σ- between vowels disappears. In the instrumental singular and plural it is noticeable that there are two suffixes—one, represented in Germanic and Balto-Slavonic only, beginning with the sound -m, the other, surviving in most of the other languages for the plural, going back to an Indo-European form beginning with -bh. Professor Hirt of Leipzig has argued (Idg. Forschungen, v. pp. 251 ff.) that -bh- originally belonged to the instrumental plural (cf. the Lat. filiabus, omnibus, &c.), and the forms with -m- to the dative and ablative. But this is merely a conjecture, which has no linguistic facts in its favour, for the -bi of the Latin dative tibi, which has parallel forms in many other languages, belongs to the pronouns, which show in their declension many differences from the declension of the noun (cf. also Brugmann, Grundriss (ed. 2), ii. 2, p. 120). (2) The adjective agrees with its noun in gender, number and case, thus introducing a superfluous element of agreement which is not found, e.g. in most of the agglutinative languages. Thus in phrases like the Greek ἡ καλὴ κόρη or the Latin illa pulchra puella the feminine gender is expressed three times, with no advantage, so far as can be detected, over the modern English, that fair maid, where it is not obviously expressed at all. In this respect and also in the employment of the same case endings for the plural as well as the singular, in the plural after a syllable expressing plurality, the agglutinative languages have a distinct superiority over the Indo-European languages in their earliest forms. Some languages, like English and Modern Persian, have practically got rid of inflexion altogether and the present difficulty with it; others, like modern German, as the result of phonetic and analogical changes have even intensified the difficulty. (3) In the personal pronouns, especially those of the first and second persons, there is widely spread agreement, but more in the singular than in the plural. Forms corresponding to the English I and thou, the Latin ego and tu, are practically universal. On the other hand the demonstrative pronouns vary very considerably. (4) The system of numerals (subject to slight discrepancies, as that regarding 1 mentioned above) is the same, at least up to 100. (5) In the verb there were at first two voices, the active and the middle, and three moods, the indicative, the subjunctive and the optative. It has been suggested by Professors Oertel and Morris in Harvard Studies, xvi. (p. 101, n. 3) that the similarity which exists between the earliest Greek and the earliest Aryan in the moods is the result of a longer common life between those two branches. But of this there is no proof, and the great difference in the treatment of the sounds by these two branches (see below) militates very strongly against the supposition. The tense forms indicated originally not relations in time but different kinds of action. The distinctive forms are the present, the perfect, and the aorist. The present indicated that an action was in progress or continuous, the aorist on the other hand regarded the action as a whole and, as it were, summed it up. The aorist has sometimes been said to express instantaneous action, and so it does. But this is not the essence of the aorist; the aorist may be used also of a long continued action when it is regarded as a whole. Greek shows this very clearly. In Athenian official inscriptions it was usual to fix the date of the record by stating at the commencement who was the chief magistrate (archon) of the year. This was expressed by the imperfect (ἠρχε). But when reference was made to a past archonship, that was expressed by the aorist (ἦρξε). The same characteristic is evident also in prohibitions; thus, in Plato’s Apology of Socrates, μὴ θορυβήσητε is “Do not begin to make a disturbance,” μὴ θορυβεῖτε is “Do not keep on making a disturbance.” These points are most easily illustrated from Greek, because Greek, better than the other languages, has kept the distinctive usages of both moods and tenses. The perfect as distinguished from the other forms expresses either repetition of the action, emphasis, or the state which results from the action expressed by the verb. Different languages regard this last in different ways. Sometimes the state resulting from the action is so characteristic that the perfect is almost an independent verb. Thus in Greek κτάομαι is “I acquire,” but κέκτημαι (the perfect) is “I possess,” the result of the action of acquiring. On the other hand the perfect may mean that the action has come to an end. This is specially common in Latin, as in Cicero’s famous announcement of the execution of the Catilinarian conspirators,—Vixerunt (“They have lived” = “They are no more”). But it is by no means confined to Latin. The pluperfect, the past of the perfect, is a late development and can hardly be reckoned Indo-European. In Greek the forms clearly arise from adding aorist endings to a perfect stem. The forms of Latin are not yet completely explained—but it is certain that the specially Latin meaning expressing something that was past at a time already past (relative time) is a late growth. When Homeric Greek wishes to express this meaning it uses most frequently the aorist, but also the imperfect as well as the pluperfect, the notion of relative time being derived from the context. In the earliest Latin the pluperfect is not uncommonly used with the value of the aorist perfect. As regards the future it is difficult to say how far it was an original form. Some languages, like Germanic, preserve no original form for the future. When the present is found not to be distinctive enough, periphrastic forms come in. In other languages, like Latin and Greek, there is constant confusion between subjunctive and future forms. It is impossible to distinguish by their form between δείξω (future) and δείξω (subjunctive), between regam (future) and regam (subjunctive). A special future with a suffix -sḭo- (syo) is found only with certainty in the Aryan group and the Baltic languages. The future perfect is, strictly speaking, only a future made from a perfect stem; in the Latin sense it is certainly a late development, and even in early Latin, videro has occasionally no different meaning from videbo. The imperative, which was originally an exclamatory form to the verb, of the same kind as the vocative was to the noun, and which consisted simply of the verb stem without further suffixes, developed, partly on the analogy of the present and partly with the help of adverbs, a complete paradigm. The infinitives of all the languages are noun cases, generally stereotyped in form and no longer in touch with a noun system, though this, e.g. in early Sanskrit, is not always true. The participles differ only from other adjectives in governing the same case as their verb; and this is not an early distinction, for in the earliest Sanskrit all verbal nouns may govern the same case as their verb.
The system here sketched in the barest outline tended steadily to fall into decay. The case system was not extensive enough to express even the commonest relations. Thus there was no means of distinguishing by the cases between starting from outside and starting from inside, ideas which, e.g. Finnish regards as requiring separate cases; without a preposition it was impossible to distinguish between on and in, though to the person concerned there is much difference, for example between being on a river and in a river. There are other difficulties of the same kind. These had to be got over by the use of adverbs. But no sooner had the adverbs become well established for the purpose of defining these local relations than the meaning was felt to exist more in the adverb than in the case ending. For this syntactical reason, as well as for mechanical reasons arising from accent (q.v.), the case system in some languages fell more and more into desuetude. In Sanskrit it has been kept entire, in Balto-Slavonic the only loss has been the disappearance of the original genitive and its replacement by the ablative. In Latin the locative has been confused with the genitive and the ablative, and the instrumental with the ablative. The loss of the locative as an independent case had not long preceded historical times, because it survives in Oscan, the kindred dialect of the neighbouring Campania. Greek has confused ablative with genitive, except for one small relic recently discovered on an inscription at Delphi; in the consonant stems it has replaced the dative by the locative form and confused in it dative, locative and instrumental meanings. In some other members of the family, e.g. Germanic, the confusion has gone still farther.
The fate of the verb is similar, though the two paradigms do not necessarily decay at the same rate. Thus Latin has modified its verb system much more than its noun system, and Greek, while reducing seriously its noun forms, shows a very elaborate verb system, which has no parallel except in the Aryan group. From the syntactical point of view, however, the Greek system is much superior to the Aryan, which has converted its perfect into a past tense in classical Sanskrit, and to a large extent lost grip of the moods. The decay in Aryan may be largely attributed to the power, which this group developed beyond any other, of making compounds which in practice took the place of subordinate sentences to a large extent. The causes for the modifications which the Latin verb system has undergone are more obscure, but they are shared not only by its immediate neighbours the other Italic dialects, but also to a great degree by the more remote Celtic dialects.
The origin and spread of the Indo-European languages has long been, and remains, a vexed question. No sooner had Bopp laid the foundation of Comparative Philology in his great work, the first edition of which appeared in 1833-1835, than this question began to be seriously considered. The earlier writers agreed in regarding Asia as the original home of the speakers of these languages. For this belief there were various grounds,—statements in the Biblical record, the greater originality (according to Schlegel) of Sanskrit, the absurd belief that the migrations of mankind always proceeded towards the west. The view propounded by an English philologist, Dr R. G. Latham, that the original home was in Europe, was scouted by one of the most eminent writers on the subject—Victor Hehn—as lunacy possible only to one who lived in a country of cranks. Latham’s view was first put forward in 1851, and in half a century opinion had almost universally come over to his side. Max Müller indeed to the last held to the view that the home was “somewhere in Asia,” and Professor Johannes Schmidt of Berlin, in a paper read before the Oriental Congress at Stockholm in 1889, argued for a close contact between early Indo-European and Assyrian civilization, from the borrowing of one or two words and the existence of duodecimal elements in the Indo-European numeral system side by side with the prevalent decimal system—the dozen, the gross, the long hundred (120), &c.