Sample problem write-up for a LING 119A/120A alternations problem
Data: Russian (Data taken from Odden 2005) (p. 69. Stress omitted. Possibly originally from Halle 1959)
• What is the genitive singular affix?
• What alternations do you observe?
This paper deals with alternations in suffixed and unsuffixed nouns in Russian.
1. Morphological rules and affix allomorphy
Genitive singulars are marked with a suffix vowel, either [-a] after a sonorant consonant or [-i] otherwise.
Because the [-i] allomorph occurs in a wider variety of environments, it must be the underlying form, /-i/. A phonological rule later on will take care of the [-a] allomorph. The morphological rule for forming genitive singulars is therefore to add i:
Genitive Singular Formation: X → Xi if X is [+genitive, +singular, +noun]
The nominative singular form is just the root, with no affixes added, so no morphological rule is needed.
2. Root allomorphy and underlying forms
Some roots have only one allomorph: [porok] ‘vice, nom. sg.’ vs. [porok-a] ‘vice, gen. sg.’ .
These non-alternating roots can end in any voiceless consonant ([p, t, k, s, ʃ]) or any sonorant
([n, lʲ , r]). Because these roots have only one allomorph, that is presumably their underlying form (/porok/).
Other roots have two allomorphs: one with a voiceless final consonant, such as [porok] ‘threshold, gen. sg.’ and one with a voiced final consonant, such as [porog-a] ‘threshold, nom. sg.’ This alternation is found for each of the voiceless/voiced obstruent pairs in the data: [ b / p ], [ d / t ], [ ɡ / k ], [ s / z ], [ ʃ / ʒ ]. The voiced-final allomorph is always found in the suffixed form, __V, and the voiceless-final allomorph is always found in the unsuffixed form, __ ]word. The voiced-final allomorph must be the underlying one (/porog/), because if the underlying form had a voiceless consonant, we would not be able to explain why these roots behave differently from the non-alternating, always-voiceless roots.
3. Phonemicization
The voiced and voiceless obstruents are all separate phonemes, but the voiced obstruents also have a voiceless allophone when word-final:
The alternation in the suffix shows that the vowel /i/ has two allophones:
4. Phonological rules
A Lowering rule accounts for the alternation seen in the suffixes:
Lowering: /i/ → [a] / [-syllabic, +sonorant] __
/i/ becomes [a] after a sonorant consonant.
A Final Devoicing rule accounts for the alternation seen in the stems:
Final Devoicing: [–sonorant] → [–voice] / __ ]word
Obstruents become voiceless at the end of a word.
5. Derivations
The following derivations illustrate how the morphological rule and the phonological rule apply. I’ve chosen one alternating and one non-alternating word, with and without the genitive singular suffix. These both take the default form. of the suffix, so one additional word is included to illustrate Lowering.