It's the difference between 'and' and 'also'. I would add a plural to 'actions' because there have to be two of them in order for this morpheme to do its job. The author was probably focused on the fact that it refers to the upcoming action, but it also refers to the preceding action.

Regarding 'additive', I couldn't find any linguistic references to "additive action," and I understand why. 'Additive' is really a subset of 'conjoined' in the context of conjoined actions. It would mean conjoined with an 'additive' meaning added (forgive the pun). In English, in formal speech we would to use two words and say "and also." In informal speech we would add a supresegmental: "She is singing AND dancing." Also, maybe "PLUS" in some contexts: "He was pitching PLUS playing first base."


Examples of "conjoined actions":

being **conjoined actions**—that is, go to the. basket and go left. Instead, ... ficient to code the overall verb-class action. The conclusion remains, ...
www.psychonomic.org/search/view.cgi?id=2044

6.6 Determining the **Relationship between Conjoined actions** . . . 37. 6.7 Verb Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 ...
www.cse.buffalo.edu/~rapaport/CVA/Verbs/sutanto-becker-740R...

If the medium were a doorknob, a verb such as "turn" would have been a ... conditionals may be expressed in text only, while **the conjoined actions** may be ...
acl.ldc.upenn.edu/H/H89/H89-2055.pdf -

... enablement) exists between the **conjoined actions**. PC fa ( Purpose Clause using a free adjunct) The purpose or goal of the action in the main verb phrase ...
citeseer.ist.psu.edu/context/375347/0


MV speaking:
... cannot be correct, since this is equivalent with **the additive meaning 'also'** ... Dougherty, R. (1970) 'A Grammar of Coördinate Conjoined Structures: I'. ...
www.ai.rug.nl/prepublications/prepubsAI-2001-10.pdf

progressive tenses, especially when it is conjoined with a genuinely ... **concatenated syntactic construction with an additive meaning**: twenty-five = ‘20 + ...
www.oup.co.uk/pdf/0-19-823780-4.pdf

Kuskokwim Athabaskan, noun phrases are conjoined by means of bisyndetic ... **additive meaning ('he and us')**. And since Hausa does not make a distinction ...
www.eva.mpg.de/~haspelmt/2004coo.pdf





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Note added at 2 hrs (2006-09-09 21:04:33 GMT)
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I forgot to delete "MV speaking" when I moved the paragraph to the top.