[developers] Hacking the DELPH-IN framework for a null morpheme: a semi-success

Woodley Packard sweaglesw at sweaglesw.org
Fri Apr 12 06:50:37 CEST 2019

Hi David,

If I understand correctly you have a lexical entry whose orthography in the lexicon is “=0” but which only ever appears in combination with the prefix or suffix or both, which lets you cover up the fact that the =0 was ever there.  Sounds reasonable to me.

Forgive me if this is too obvious and not what’s going on, but:  getting two parses when both suffix and prefix are present seems likely to be caused by unconstrained order of application of those rules.  Have you checked whether the two parses you get have the rules applying in opposite orders?  If so, the solution is simply to constrain things so that one of them cannot consume the other’s output.

If on the other hand the two parses have identical derivations then the result is unexpected — at least under the currently used definition of derivation trees.  There have been suggestions that derivations with different internal inflected string values resulting from different subrules of the %prefix and %suffix mechanisms should be considered distinct (and that those should be recorded as part of the derivation tree), but to my knowledge none of our systems supports that yet, nor do I believe a format has been decided upon.


> On Apr 11, 2019, at 8:56 PM, David Inman <davinman at uw.edu> wrote:
> Hello developers,
> I am using the irules to define a null morpheme by having prefixes and suffixes overwrite a string (=0, 3rd person marking on a clitic complex) when they attach to it. The irules look like this:
> past-prefix-2 :=
> %prefix (* =int) (=0 =int)
> past-lex-rule.
> clitic-plural-suffix :=
> %suffix (* =ʔał) (=0 =ʔał)
> clitic-plural-lex-rule.
> This works and generates strings that are lacking the =0 morpheme. Except that in the case where both a prefix and a suffix attach, the parser enters two =0 morphemes into the parse chart and will parse it doubly. (This does not happen for contentful roots.) If the =0 has only "suffixes" after it, then I get one parse. If it has only "prefixes" then I also get one parse. I think the parser sees that =0 can be overwritten either by the prefix or the suffix so it hypothesizes it twice. I'm using the morph rules a bit differently than intended, but is this a case that should be supported? Is there any way around this so that I limit the parsers behavior and get one parse?
> David Inman
> PhD Candidate
> University of Washington Linguistics
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