2 Different Grammar Patterns formed from the word かねる and its Negative Form かねない (Pre-ます-Form VERB + かねる as “to not be able to do VERB” and Pre-ます-Form VERB + かねない as “for VERB to be likely to happen”)
The word かねる can be used to form two different grammar patterns depending on whether it is used in its positive form (かねる) or its negative form (かねない). The construction for both versions includes the Pre-ます-Form of a VERB word that immediately precedes it.
Pre-ます-Form VERB + かねる = “to not be able to do VERB”
Pre-ます-Form VERB + かねない = “for VERB to be likely to happen”
1.) When the Pre-ます-Form of a VERB word is used with the positive form かねる, the grammar pattern formed acquires the meaning of “to not be able to do VERB.” Or, “to find it difficult, unpleasant, awkward, painful to do VERB.” This grammar pattern is very formal and is more commonly seen in written Japanese than heard in spoken Japanese. In most cases wherein it does show up in conversational Japanese, it is in a formal situation and setting, such as a businessman speaking to his superior.
2.) When the Pre-ます-Form of a VERB word is used with the negative form かねない, the grammar pattern formed acquires the meaning of “for VERB to be likely to happen,” in which VERB is an adverse action that is undesired. This generally in turn means that the VERB word used is not an action that the speaker himself performs (but rather, an outside action that negatively affects the speaker or entity related to the speaker). This grammar pattern that is used with the negative form かねない is also considered a formal grammar pattern that is more commonly seen in written Japanese than heard in spoken Japanese, but it can occasionally show up in conversational Japanese, even beyond formal scenarios.
(“I apologize, I do not understand.”)
Sonnani hayaku shitara, misu wo shikanenai.
(“If you work on it at such a quick pace, it’s likely that you’ll end up making a mistake.”)
Koutsuuryou ga fuekanenai kara, hayaku dekaketa hou ga ii.
(“There’s likely to be a lot of traffic, so it’d be best to leave as soon as possible.”)