The Proto-Indo-European sḱé-present is reconstructed on the basis of a variety of reflexes in numerous daughter languages, many of which showcase divergent semantic developments, complicating the identification of the original function of the formation. Nevertheless, it is usually ascribed an iterative, durative, or inchoative value.

Structure That there was an original palatovelar in the suffix is perhaps supported by the Anatolian evidence. According to the linguist Craig Melchert, the Luwian suffix may have emerged due to the simplification of earlier , itself the regular reflex of Proto-Indo-European . Moreover, if the existence of a palatovelar is accepted, then Lycian is also adducible as a cognate, as is the expected Lycian reflex of Proto-Indo-European . Regarding the components of the suffix, the linguist Norbert Oettinger has suggested that it may comprise the elements and ('now, here'). According to Oettinger, the particle was added to the imperative forms of verbs (i.e. 2s.impv. perhaps was reanalyzed as ). Similarly, Jasanoff has proposed that the suffix consisted of a morpheme and a thematic suffix . According to Jasanoff, the first component is perhaps connected to the desiderative suffix , in which case the suffix was itself was once possibly of the shape . However, this proposal would require the deletion of the laryngeal following both sonorants and obstruents, whereas the thematic desiderative present appears to have only dropped the laryngeal prior to the latter consonant type. To remedy this issue, Jasanoff suggests that that the laryngeal was omitted due to a special sound law concerning clusters of the shape . or the analogy of obstruent-final roots. Another linguist, C. J. Ruijgh, proposes that the possibly served as a marker of telicity and the suffix at large functioned to derive imperfective telic terms from perfective telic verbs. Rujigh does, however, concede that this theory, though "tempting", is "difficult to prove". Alternatively, the linguist Andreas Willi has suggested that the first component of the suffix was merely a perfectivizing marker. However, Willi suggests that the addition of the second component, probably served to reimperfectivize the overall term. Regarding the nature of this second element, Willi suggests that may equate to the k-extension present in terms such as Ancient Greek (, 'to melt'), from , an enlargement of ('to melt').

Ablaut Sihler reconstructs the form as thematic, with zero-grade root and accent on the suffix. Such an ablaut paradigm is continued in Hittite, where the suffix—which remained productive—utilized the zero-grade of the root, as demonstrated by the form , which derives from the verb ('to drink'). Despite the usual zero-grade vocalism of -presents, Sihler reconstructs at least one possible full-grade form: , which is possibly the source of Latin and Ancient Greek (). However, the existence of the full-grade in this term is not universally accepted, with linguists such as Michiel de Vaan opting to reconstruct . Tocharian B and Latin perhaps also reflect a full-grade term of the shape , though de Vaan likewise suggests possible zero-grade pre-form for the Latin term. Jasanoff argues that certain irregular full-grades emerged due to contamination with an s-present, noting the coexistence of alongside the Hittite s-present . Jasanoff further explains the irregular full-grade in Classical Armenian ('to ask'), which he derives from ('to be searching'), as the result of such influence from s-presents. Willi suggests that a pre-form of the shape once served as the imperfective counterpart to the sigmatic aorist, whereas a separate form later emerged as an imperfective counterpart to the root aorist. This new formation acquired the zero-grade in the root as a parallel to the zero-grade of the weak stem of the root aorist, just as the other formation paralleled the full grade of the weak steam of the sigmatic aorist.

Semantics

Within PIE According to Jasanoff, the original semantic function of the suffix was possibly desiderative, perhaps with an additional somewhat conative sense. Sihler suggests that it is possible the unify the disparate reflex of this PIE formation under a single originally iterative-durative suffix, as he argues that it is generally common for iteratives to evolve to denote past habitual action. Jasanoff proposes that the iterative sense perhaps secondarily emerged from an earlier desiderative purpose, with an original desiderative meaning of 'to be disposed to be or do something' shifting to describe habitual actions, which possibly allowed for a transition towards an iterative function. Moreover, Jasanoff suggests that the desiderative meaning would have been functionally identical to the sense 'to be in the initial stages of doing or becoming something', which would perhaps have allowed for the acquisition of inchoative semantics. The iterative use potentially emerged from the causative function, perhaps in the same manner as the causative-iterative suffix .

Willi, however, suggests that the suffix originally lacked any specific lexical aspect and instead merely possessed a generically imperfective value. According to Willi, iterativity is itself a necessary by-product of any imperfective formation, and that the inchoativity of descendants—such as Latin —only emerged due to the influence of the stative morpheme . Ultimately, Willi suggests that the suffix, in his earliest incarnation, formed imperfective verbs from root aorists, such as , which exists beside the root aorist . However, this suffix—and the corresponding zero-grade ablaut—eventually spread to other roots, thus explaining the existence of verbs such as () (< ), which exists beside a root present ('to speak, be talking'). In contrast to Willi, the linguists Guglielmo Inglese and Simone Mattiola have proposed that the suffix only acquired more general imperfective meanings as a consequence of secondary developments in the daughter languages, whereas the original suffix functioned largely as a marker of iterativity or pluractionality. Inglese and Mattiola argue that crosslinguistic studies on the semantic development of originally iterative formations reveal a general trend wherein iterativity shifts towards imperfectivity. They nevertheless concede that their proposed scenario is "speculative" and requires comparison with a more rigorous internal reconstruction of the semantics of this suffix and the PIE aspect system.

Across the daughter languages The original meaning of the suffix has been partially obscured by the multivarious functions it acquired in the daughter languages: The Latin suffix forms inchoative-intransitive verbs, whereas the Tocharian reflexes form causatives. Beside Tocharian, there are other examples of causative -presents, such as Ancient Greek (, 'to cause to drink'). In Ancient Greek, the () verbs are divisible into three major subgroups based upon their semantics. Aside from the aforementioned causative verbs, there were also certain inchoative terms, such as (, 'to grow old'), and also verbs that showed no unique semantic characteristics and were indistinguishable from an ordinary present, such as (, 'to please'). The causative forms are often transitive and opposed to stative base verbs, such as (; 'to intoxicate, make drunk'), which exists alongside the base verb (, 'to be drunk'). Likewise, the inchoative verbs also exist opposite to stative verbs, yet they are usually intransitive themselves, such as (, 'to begin to grow a beard'), which exists parallel to ('to have a beard').

Whereas the exact function of the suffix in Classical Greek is unclear, in Homeric and Ionic Greek, the suffix appears to have remained productively capable of forming words that described habitual activities, such as the term (, 'was accustomed to give'), which belonged to the verb (, 'to give'). This suffix could create new imperfect or aorist tenses for verbs that otherwise lacked the -morpheme, such as the imperfect form (, 'they would [habitually] flee'). Like Ionic Greek, the Hittite suffix also could form an imperfective variant of a base verb, such as ('to give'), which is an iterative counterpart of ('to give, pay'). This shared feature between Greek and Hittite has been explained as the result of areal contact between a dialect of Late Mycenaean Greek and a 13th-century BCE dialect of Hittite.

Similarly, in Classical Armenian, the aorist—which largely continued the PIE imperfect—can contain a () extension, which may also derive from the -suffix. It has been proposed that these Armenian and Greek formations are connected to each other, though the phylogenetic proximity between Armenian and Greek is not uncontroversial, and the linguist James Clackson proposes that these verbal formations are merely separate innovations. There are certain differences in the particular characteristics of the Armenian and Greek formations—Armenian weak aorists to monosyllabic stems are always augmented in the active third-person singular (i.e., , 'stood'), whereas the Ionic iterative imperfects frequently lack the augment. Moreover, Ionic Greek primarily utilizes () to form iterative imperfects, whereas Armenian instead largely uses .

The related Avestan suffix appears to have formed a past tense with a habitual meaning, though there is no semantic difference in the present tense. Otherwise, amongst the Iranian languages, the suffix is associated with inchoative semantics. For instance, the suffix appears in the inchoative Ossetian verb ('to become hot') and the Khwarezmian verb ('to wake up'). In Indo-Aryan, however, the Vedic Sanskrit verbs marked by the suffix , such as ('to go'), appear to showcase no identifiable semantic difference from other terms. In Hittite, this suffix remained productive, and—according to Sihler—it usually formed iterative verbs, though it could also seemingly produce terms with durative meanings. Alternatively, Kloekhorst argues that the Hittite suffix could communicate a wide array of imperfective meanings, be they iterative, distributive, durative, ingressive, and progressive. The Hittite suffix is often associated with exclusively mediopassive verbs, such as ('to become tall'), which forms a mediopassive imperfective verb . Moreover, in Latin, there is a group of ancient deponent verbs in that lack any corresponding present or perfect stems, such as ('to be born') and ('to depart'). There is little attestation for the suffix in the other Anatolian languages beside Hittite, though the Luwian verb ('let last, let endure') displays a continuative function and the verb ('become hostile') showcases inceptive semantics.

Reduplicated sḱé-presents The term (') perhaps represents a particular type of reduplicated -present, which is perhaps continued in other words such as (; 'to eat, swallow up') or (, 'to teach'). According to Sihler, these forms—in Ancient Greek—are often marked by their transitivity. There is perhaps evidence of a similar formation in Latin, with the term ('to learn') possibly deriving from . In Hittite, there is likewise a connection between initial reduplicated and -presents, as demonstrated by forms such as , which may reflect . Certain Ancient Greek reduplicated -presents coexist alongside unreduplicated variations of the same form, such as (), which exists beside (). Both the LIV and Beekes suggest that the reduplicated form probably emerged as a secondary development from earlier (), itself perhaps from Proto-Indo-European . Regarding this particular form, however, Willi suggests that it probably emerged later as an artificial creation. Another such verb, (; 'to appease, to conciliate'), which appears to reflect Proto-Indo-European , is probably cognate with Old Armenian ('to pray'), which itself possibly continues quasi-Indo-European .