Editing Distributed morphology (section)

=== Containment hypothesis ===
The containment hypothesis is a theory under the framework of Distributed Morphology advanced by Bobaljik (2012) to account for the restrictions on the patterns of [[suppletion]] seen in language. It states:<blockquote>''"The representation of the superlative properly contains that of the comparative (in all languages that have a morphological superlative)."''<ref name=":0" /></blockquote>Bobaljik argues that if a language has a [[superlative]] form, it must build off the comparative form. In other words, the superlative form and the bare adjective cannot be built off the same root to the exclusion of the comparative (a so-called *ABA pattern), because the comparative is necessarily ''contained'' within the superlative form. Thus, languages allow:
# AAA: All three forms to be built off the same adjectival root
# ABB: The comparative and superlative are suppletive and thus built off a different root from that of the bare adjective
# ABC: The bare adjective, comparative, and superlative are all built off different roots
{| class="wikitable"
!Pattern
!'''Language'''
!Adjective
!'''Comparative'''
!Superlative
|-
| rowspan="3" |AAA
|[[Persian language|Persian]]
|X
|X-tær
|X-tær-in
|-
|[[Hungarian language|Hungarian]]
|X
|X-bb
|leg-X-bb
|-
|[[Chukchi language|Chukchi]]
|X
|X-əŋ
|ənan-X-əŋ
|-
| rowspan="2" |ABB
|[[English language|English]]
|good
|better
|best
|-
|[[Czech language|Czech]]
|špatn-ý
'bad'
|hor-ší
'worse'
|nej-hor-ší
'worst'
|-
|ABC
|[[Latin]]
|bonus
'good'
|melior
'better'
|optimus
'best'
|}
The exclusion of the *ABA pattern means that there should theoretically exist no language with a pattern analogous to *''good – better – goodest''. AAB patterns (in which the superlative is suppletive but the comparative builds off the bare adjective) are theoretically possible as well but happen to be rare in the world's languages. Under the model of Distributed Morphology, the structure of a superlative would be [<sub>SPRL</sub> [<sub>CMPR</sub> [<sub>ADJ</sub> Adjective ] Comparative ] Superlative ]. Thus, the exponent of the comparative morpheme attaches to the bare adjective and the exponent of the superlative morpheme attaches to the comparative form (or replaces it in the suppletive cases). The following rules may be posited for Czech as an example:<ref name=":1" />
# √BAD → špatn-
# √BAD → hor- / ___ CMPR
# CMPR → -ší
# SPRL → nej-
Rule 2 above states that the root BAD is suppleted in the environment of a comparative. By extension, the superlative form attaches the prefix ''nej-'' to ''horši'' and not to ''špatn-'' as the comparative is the only structure it can see. For Latin, in which both the comparative ''and'' the superlative are suppleted, the following rules may be posited:<ref name=":1" />
# √GOOD → bon-
# √GOOD → mel- / ___ CMPR
# √GOOD → opt- / ___ SPRL
# CMPR → -ior
# SPRL → -imus
As an *ABA pattern would require the adjective to directly combine with the superlative node, it is theoretically impossible because of the intervening comparative node and is also unattested in the world's languages. Nevins (2015) supports the structure by arguing that the semantics of the superlative is dependent on that of the comparative.<ref name=":1" />
# Comparative: Y is more ADJ than X
# Superlative: For all X, Y is more ADJ than X
The comparative definition is contained within the superlative one and thus, the superlative must obligatorily subsume it in its structure.