If Indo-European possessed such a large array of deictic adverbs as is claimed by Hirt in his Indogermanische Grammatik then it is inconceivable that they were used indifferently; there must have been a more specific meaning associated with the various particles, for primitive man attaches importance to exact location and direction. On the basis of the later known meanings of some of these words we may assume tentatively at least the following earlier meanings: i, me, ke, ge meant ‘here’; e, se, te, pe, ne, and u meant ‘there’; a meant ‘direction toward’. These particles formed contrast pairs out of which new uses developed. I offer the following suggestions :
C. M. Lotspeich (Mon,) studied this question.