I use the comprehensive term 'particles' for adverbs, prepositions, and conjunctions, as these three "parts of speech" have so much in common that they are best treated together. A preposition may be called a transitive adverb having a noun or pronoun as its object; those conjunctions which serve to introduce a subordinate clause are adverbs (prepositions) having a clause as their objects; other so-called conjunctions (e.g. and) are simply particles used to join words or clauses.
There is no necessity of a special ending for all particles or for any special sub-class of them; not even Esp carries through the ending -e for all adverbs and -au for prepositions. We keep therefore the forms of those languages from which, among others, the following particles are taken:
nun now. nur only. preske nearly, almost. quasi as if, as it were, so to speak. bald soon.
In accordance with our usual practice we make a distinction between interrogative quand (when? D wann? F quand?) and relative (connective) kand (when, introducing a clause, D wenn, als, F quand, lorsque): kand lo departad, lo non dikted quand lo sal veni retro when he left, he did not say when he will come back; and then we form regularly the corresponding demonstrative tand (then, D dann, damals, F alors).
E and. It is inconvenient to use a repeated e . . . e for 'both . . . and'; the English way, which is also found in Sc (cp. D sowohl . . . als), is better because it at once prepares the hearer that something is to follow. I propose et . . . e: me vidad John, e et lon fratro e lon patro esed dar. Nus et audid e vidad lo. La montrad a nus et sen patro e matra (where e . . . e would be ambiguous).
In the same way o or, od . . . o either . . . or (od, cp. D oder); ni nor, nek . . . ni neither . . . nor.
Ma but (F I S, resembles Sc men, Dutch maar).
Tamen (L) yet, however, notwithstanding -- used in most interlanguages, as living languages offer no convenient word (malgreu, in Prepositions).
Or as in F to introduce a new element in arguing (E now): lo dikte ke lo non esed dar; or me self vidad lo dar; dunke lo mentia he says that he was not there; now I saw him there myself; thus he is lying.
Dunke (I dunque, F donc) consequently, therefore.
Den (D denn) for (to indicate reason; F car); there is no necessity to go to Latin nam, as D denn is perfectly unambiguous (Pirro already had den): lo mus ha es dar, den me vidad lo.
Kom (F I S) as: kom li presidanto me konsidera li afere kom finat. On representa lo kom avaro (a miser). Exept si vus deveni kom mikri infantes. Autores kom Shaw (kom exemplim Shaw). Kom yuno lo vivad in London. Kom me ha ja dikte. La viva kom anteu - kom la ha omnitem fa (= samiman kam la . . .). - Kom ministro lo dikte, in his capacity as minister; this can, if necessary, be rendered more precise by saying esenti ministro, or kom esenti ministro.
Under Comparison we mentioned tam (demonstrative) and kam (connective). Further examples: tam bon kam novi as good as new, as a new one. Tam bald kam posibli as soon as possible. Lo marcha non tam rapidim kam in sen yuneso. Kom home lo es tam grandi kam kom poete (= egalim grandi). Tam mikri ke on pove apene vida lum so small that one can hardly see it. Tum es tam plu surprisivi pro ke . . . so much the more. Kam plu oldi, tam plu stupid the older, the more stupid. Kam plu on vida lo, tam min on estima lo.
The corresponding interrogative is quam: quam oldi how old? Quam multum = quantum. Qualim me pove sava quam oldi lo es? How can I know how old he is?
Anke (I) also: anke me dikte I too say; me anke dikte or me dikte anke I say also; anke me non dikte or me anke non dikte I also do not say, neither do I say.
Ankore (F I) yet, still: lo es ankore maladi (has been ill for some time and is still, though you might have expected otherwise); lo ha non ankore ariva (not yet). Lo es richi, ma lon fratro es ankore plu richi (still richer, encore plus riche, noch reicher).
Preske (F) nearly, almost.
Apene (F S I) hardly, scarcely (= preske non).
Even (E): by taking even and self instead of Ido mem (F) and ipse (L) we gain the advantage of having words which are known to several more millions of people and which are unambiguous, while mem is apt to induce all those who know French to use it in the meaning either of N self (F lui-même) or of N sami (F le même).
Erste (D) not till: li kunvenio komensad klok du, ma lo venid erste klok tri.
Jus just now, a moment ago (D . . . S, here as in Esp and Ido differentiated from justi, justim).
Sat (L, but cf. satisfaction) enough: sat boni good enough; sat multi tempe time enough.
Tro (F) too: tro tardim too late. La parla tro.
Plu, min, see Comparison. Plus in the combination non plus no longer; nulum plus no more, nothing else. (Du plus tri. Mil yares e plus). Tre very: tre bon.
Ke that, conjunction: me dikte ke tum es ver; corresponds with its initial k to the other relative (i.e. clause-connecting) words. Combined with prepositions: pro ke, sin ke, etc. see Prepositions.
Si (F S L si, I se) if; si non if not, unless; si nur if only.
Quasi (L I S, often used in other modern languages) as if, as though: lo akte quasi lo es (esud) maestro. Often without a verb: lo es quasi patro a me ('as it were'). Komunisme es quasi religione.
Ja already (F I).
Ya (D Sc) indeed, truly (to confirm a statement or admit a fact): vu non besona dikte tum; me ya savad lum ja you need not tell me that, as I knew it already, ich wusste es ja schon. Atente! Ma me ya atente. But I do pay attention.
No (E F I S).
In most constructed languages ne is used as the ordinary negative adverb; in spite of this unanimity, however, ne is not the best form that can be selected. As I have shown in a separate volume (Negation in English and other Languages, Acad. of Copenhagen, 1917), the natural development in many languages has led to the giving up of the simple form ne, which is felt to be too light and too little susceptible of the emphasis which is often required with this word for the sake of contrast; thus ne was supplanted by fuller forms; non in Latin, not in English, nicht in German, ikke in Scandinavian, ne . . . pas in French, which in everyday speech tends to become pas without ne. Therefore it is better to use the fuller form non, which is known in many lands through such words as nonsense, nonchalant, nonconformist; it is the ordinary negative in Italian, and is extensively used in F: non-obstant, non seulement, etc., E: non-existent, non-collegiate, non-alcoholic, etc., to which may be counted none-the-less, none too soon, though the etymology and the sound of the vowel is different.
Non may also be used as a prefix, see Prefixes: nonrational irrational; nonnesesarieso (better than Ido neneceseso), etc.
It is necessary to have a particle indicating question, i.e. those questions which are not introduced by an interrogative pronoun or adverb, like Who? What? When? How? --in other words for those questions which my Philos. of Grammar are termed nexus-questions, and which generally demand Yes or No in the answer. Word-order with preposed subject (as in E "Are you ill?") cannot well be used in an IAL; and it is evidently best to have one and the same particle in direct and indirect questions (he asked if, or whether, you were ill). The difficulty is to find a particle which is at once natural and unambiguous.
Zamenhof took his native Polish word czy, only modifying it to chu. Ido went far away to Sanskrit to find ka, which, by the way, does not seem to be used in Sanskrit in exactly the same way; it might have been mentioned that Japanese has an interrogative particle ka, only placed at the end of the sentence (Edwards, Ét. phon. de la L. Jap., § 135); Finnish, too, has an enclitic -ko, -kö to denote questions. Occ uses E if in dependent questions; this is not good as it may be taken to mean condition. Russian li (postponed) is out of the question.
There is, however, one word in a well-known language that seems to me to fulfil all the requirements, namely D ob. This at first was used in dependent questions (wer weiss, ob er kommt), but is now used pretty often in direct questions as well (Ob er kommt?). I propose in Novial to use the same word in both applications: Ob lo veni? Does he come? Que sava ob lo veni? It may even be used put twice (as Z uses cxu . . . cxu) to denote two alternatives (Ido from L sive . . . sive), as in rendering Goethe's "Er liest es jedem froh und laut, Ob es uns quält, ob es erbaut!" Lo lekte lum a chake lautim joyosi, ob tum jena nus, ob tum edifika nus. Ob vu silentia, ob vu parla, on sal blama vu, whether you say nothing or speak, they will blame you.