א, ה, ו, י, and נ are traditionally known as weak letters in Biblical Hebrew. Their instability stems from their phonological behavior—tending to elide, assimilate, or transform—and their frequent influence on neighboring vowels. These letters regularly disrupt root visibility and produce irregular morphology in verbs and nouns. Their effects are especially notable in verb classes such as I-א, I-י, I-נ, II-ו/י, and III-ה, where they affect prefix forms, syllable structures, and noun derivations. Weak letters are not defects in the system but signs of linguistic flexibility and poetic refinement.
What Makes a Letter “Weak”?
Weak letters are not phonetically weak but morphologically volatile. They either cannot carry a dagesh (e.g., א, ה), often function as semivowels (e.g., ו, י), or assimilate entirely (e.g., נ). Their interactions with vowels and stress produce significant morphophonological shifts, which are visible across Hebrew verbal paradigms and noun structures.
Categories of Weak Letters
| Weak Letter | Hebrew | Morphological Behavior |
|---|---|---|
| ʾAlef | א | Silent/quiescent; drops in conjugations; affects vowel structure |
| He | ה | Feminizing; final ה often elides in derived and construct forms |
| Waw | ו | Consonantal or vocalic; part of diphthongs; merges with vowels |
| Yod | י | Semivowel; forms diphthongs; disappears in contractions |
| Nun | נ | Assimilates to following consonants, especially in Niphal and Hiphil |
Phonological Effects of Weak Letters
1. Elision and Contraction
- אָמַר (“he said”) → יֹאמַר (“he will say”) — א quiesces; qamatz becomes ḥolem
- יָצָא (“he went out”) → אֵצֵא (“I will go out”) — initial י contracts with prefix
- נָפַל (“he fell”) → אִפֹּל (“I will fall”) — נ assimilates in 1cs imperfect
2. Compensatory Lengthening
- גָּלָה (“he uncovered”) → גָּלוּ (“they uncovered”) — final ה drops; vowel lengthens
3. Assimilation
- נָתַן (“he gave”) → יִתֵּן (“he will give”) — נ assimilates into tav
Major Weak Verb Classes
| Verb Class | Description | Example |
|---|---|---|
| I-א | Initial א affects prefix vowels | אָמַר → יֹאמַר |
| I-י | Initial י contracts or elides | יָצָא → אֵצֵא |
| I-נ | Initial נ assimilates in certain stems | נָתַן → יִתֵּן |
| II-ו/י | Waw/Yod in middle; unstable vowel patterns | קוּם → יָקוּם |
| III-ה | Final ה drops in imperfect and construct forms | בָּנָה → יִבְנֶה |
Additional Phonological Patterns
Shewa and Weak Roots
- Weak letters often resist bearing a vocal shewa
- Preceding vowels are lengthened or altered for compensation
- Resulting forms include closed syllables or glide insertions
Diphthong Resolution
- Original diphthongs aw and ay resolve to ō and ē
- Example: בַּיִת (bayit) → בֵּית (bēt) in construct
- Yod and waw may collapse into long vowels under suffixation
Effects on Nominal Morphology
Weak roots also affect noun formation, especially with construct forms:
- תּוֹרָה → תּוֹרַת (“law” → “law of…”) — final ה drops
- מָוֶת (death) shows irregular behavior from the II-ו root מ־ו־ת
Implications for Syntax and Exegesis
Understanding weak letters helps:
- Distinguish homographs: e.g., יָד (“hand” vs. “memorial” in context)
- Recognize verbal stem identity even when radicals disappear
- Clarify poetic ellipses or chiastic forms involving elision
Poetic and Theological Dimensions
In poetry, weak letters contribute to rhythm, meter, and assonance. Their elision shortens lines or creates symmetry between cola. Theologically, the morphophonological “softness” of divine names (e.g., יְהוָה with final he) aligns with notions of reverence and ineffability. These letters allow for layered meanings in sparse verbal structures, revealing theological richness in morphology itself.
