Infinitivus pro participio (IPP) or Ersatzinfinitiv is a linguistic phenomenon occurring in a subset of the West Germanic languages, such as Dutch, German, and Afrikaans. IPP refers to constructions with a perfect auxiliary, in which an infinitive appears instead of the expected past participle. In Afrikaans, one expects the temporal auxiliary for the perfect tense to select a past participle, cf. gebly in example (1a). However, when a verb occurring in the perfect tense selects another verb, it commonly occurs as an infinitive, cf. bly in example (1b), instead of the expected past participle, as illustrated in example (1c). (1a) Hy het stil gebly. (1b) Hy het bly praat. (1c) Hy het gebly praat. Ponelis (1979), De Vos (2001), and Zwart (2007) report that IPP appears optionally in Afrikaans. This contrasts with Dutch and German, as in those languages IPP is obligatory for certain verbs. Donaldson (1993) mentions however that IPP is triggered in most cases, such as in example (1b). Constructions with a past participle such as (1c) do occur, but Donaldson considers them non-standard Afrikaans. Apart from double infinitive constructions, there is a second construction in which IPP can be triggered. Afrikaans has a serialization pattern using the conjunction en (and) in order to express the continuous or progressive aspect of the verb, as in example (2a). Such constructions also exist in Danish (e.g. Du havde måttet sidde og lære dine lektier ‘You should have done your homework’) and English (e.g. He sits and reads), but not in Dutch nor German. If this construction is put in the perfect tense, the first main verb has optional ge-marking, so it optionally triggers IPP, while the second main verb always occurs in the infinitive, as shown for the verb staan in examples (2b-c). Both forms are considered standard Afrikaans by Ponelis (1979), Donaldson (1993), and Zwart (2007). (2a) Ons staan stil en luister. (2b) Ons het stil staan en luister. (2c) Ons het stil gestaan en luister. Compared to well-resourced languages such as English and Dutch, NLP tools for linguistic analysis in Afrikaans are still not abundant. In order to facilitate corpus-based linguistic research for Afrikaans, we are creating a treebank based on the Taalkommissie corpus. We adapted a tokenizer and a shallow parser, while using the TnT tagger to do part-ofspeech annotation. In Augustinus and Dirix (2013), we used these tools to investigate the occurrence of IPP in Afrikaans. The case study on IPP triggers in Afrikaans shows that a corpus-based study can shed a new light on the descriptive research of a linguistic phenomenon. Based on the literature, the hypothesis is that, in contrast to Dutch and German, IPP occurs optionally in Afrikaans. The corpus results, however, reveal that infinitive-selecting verbs in double infinitive constructions appear as IPP in almost 99% of the constructions under investigation. The results of the progressive constructions are more consistent with the current literature, since the IPP phenomenon optionally occurs in such constructions (i.e. in ca. 50% of the cases). Moreover, we can conclude that verbs that occur as IPP verbs in the double infinitive construction, do not occur as IPPs in the progressive construction and vice versa. Building on a corpus investigation of Dutch and German IPP constructions (Augustinus & Van Eynde, in press), we will include the Afrikaans data in a cross-linguistic typology of IPP verbs, in order to get a more accurate description of the differences and similarities regarding IPP across languages.