-OGY. Words derived from the Greek change Y into IO, as:—Geology = geologio, theology = teologio. The adjectives of these words end in -IC and -ICAL, and, as their Esperanto root ends in -I, A must be added to this to form the adjectives geologia, teologia.
-SIS. = ZO generally, as:—Apotheosis = apoteozo, hypothesis = hipotezo, oasis = oazo, synthesis = sintezo.
-TH. = T, as:—Hyacinth = hiacinto.
-TION. = CIO occasionally, as:—Declaration = deklaracio, exposition = ekspozicio, arbitration = arbitracio, generation = generacio, situation = situacio. Usually, however, English -tion corresponds to Esperanto -o, -ado, or -aĵo, as:—information = inform-o, -ado, -aĵo; and such forms are often used even when an alternative form in -cio exists, thus: deklar-o, -aĵo.
-UM. = O generally, as:—Epithalamium = epitalamio, gymnasium (college) = gimnazio, geranium = geranio.
-Y. = IO generally in words derived from Latin or Greek, as:—Philosophy = filozofio, astronomy = astronomio, sympathy (liking) = simpatio, industry = industrio.
53. GRAMMATICAL TERMINATIONS
(Gramatikaj Finiĝoj).
| A | final denotes | an Adjective. Patra, paternal. |
| E | final denotes | an Adverb. Patre, paternally. |
| I | final denotes | the Infinitive Mood. Fari, to do. |
| O | final denotes | a Noun. Patro, a father. |
| U | final denotes | the Imperative Mood. Faru, do. Li faru, let him do. Diru, ke li faru tion, say he is to do that. |
| J | final denotes | the Plural. Patroj, fathers. |
| N | final denotes | the Accusative Case. Patron. Mi vidis mian patron, I saw my father. |
| AS | final denotes | the Present Tense. Mi faras, I do, or, I am doing. |
| IS | final denotes | the Past Tense. Li faris, he did, or, he has done. |
| OS | final denotes | the Future Tense. Ni faros, we shall do. |
| US | final denotes | the Conditional Mood. Vi farus, you should, or would, do. |
| ANTA | final denotes | Present Participle Active. Faranta, doing. |
| INTA | final denotes | Past Participle Active. Farinta, having done. |
| ONTA | final denotes | Future Participle Active. Faronta, about to do. |
| ATA | final denotes | Present Participle Passive. Farata, being done. |
| ITA | final denotes | Past Participle Passive. Farita, having been done. |
| OTA | final denotes | Future Participle Passive. Farota, about to be done. |
N.B.—There are three forms of participles, the adjectival, substantival, and adverbial. The one given above is the adjectival. In the adverbial form the final A is changed into E. Farante tion, li … = By (in, or through) doing that, he … To form the substantive, change A into O. La faranto = The doer (the person doing). These three forms are applicable to all the three participles in both the active and passive voices (see pars. 208–210).
LIST OF SUFFIXES (Sufiksoj).
54. The following lists of suffixes (31) and prefixes (7 in number) should be carefully studied, since innumerable words of the finest shade of meaning can be formed by their aid, in fact, they are the ground-work of the language. In cases where a suffix can be used as a root, the word it helps to form is given. The hyphens are used only to show the root, suffix, and grammatical termination of the examples. The student should form other words himself, and study the works of the best authors. (For remarks on suffixes and prefixes, see pars. 270–290.)
-AĈ- Denotes badness of quality or condition (aĉ-a, vile, bad), (par. 271):dom-o, a house, dom-aĉ-o, a tumble-down house.ĉeval-o, a horse, ĉeval-aĉ-o, a sorry nag.
-AD- Denotes the continuation of an action (par. 270):paf-o, a shot, or discharge, paf-ad-o, a firing, fusillade.ir-i, to go, ir-ad-i, to continue going.
-AĴ- Denotes some real or concrete thing made from, or having the quality of, the root (aĵ-o, a thing), (par. 271):mola, soft, mol-aĵ-o, a soft thing, or substance.frukt-o, fruit, frukt-aĵ-o, jam.
-AN- Denotes