Bilingual suppletion comes from selection conflicts: Supporting evidence from Pichi

Azeb Amha recently directed my attention to a very interesting passage in Kofi Yakpo's grammar of Pichi, the English-based creole spoken in Equatorial Guinea. In this language, English-based numerals are used up to seven (and known in theory by some speakers up to ten), while Spanish numerals are familiar to all speakers and are used consistently above seven. The English numerals are followed by singulars (plural marking in Pichi is handled with postposed dɛ̀n, and occasionally the suffix -s):

So	à	dɔn	gɛt	tri	nacionalidad	nà	dis	wɔl.
so	1SG.SBJ	PRF	get	three	nationality	LOC	this	world
‘So I have three nationalities in this world.’ [fr03ft 102]

When Spanish numerals are used, however (p. 545), we get "bilingual suppletion" (Matras 2012) - i.e., a grammatical rule of one language that seems to require switching into another one:

The attributive use of Spanish numerals goes along with the insertion of Spanish head nouns – there is no instance of a mixed combination of a Spanish numeral and a Pichi noun:

Lɛf=àn	mek	è	rich	a	los	quinze	años.
leave=3SG.OBJ	SBJV	3SG.SBJ	reach	to	the.PL	fifteen	years
‘Leave her, let her reach [the age of] fifteen years.’ [ab03ay 138]

In Spanish, of course, numerals other than 1 select for plural nouns.

Now I would prefer to see a wider range of examples before reaching any firm conclusions, because counters like "years" are inherently more likely to cause borrowing of numeral+noun units. But, as described, this language precisely fits the explanation proposed for bilingual suppletion in Souag & Kherbache (2016), based on Myers-Scotton's Embedded Language Island Hypothesis:

[W]here bilingual suppletion in numeral+noun combinations emerges, it will occur only following borrowed numerals whose noun selectional requirements in the source language differ from those in the recipient language.

I was, of course, unaware that Pichi displayed bilingual suppletion when I proposed this generalization, so I take this as corroborating evidence. I would be interested to hear of any further examples.