Stylometric and Multidimensional Register Analyses

• Stylometric and multidimensional register analyses are quantitative evaluations of writing style that measure lexical, syntactic, and morphological patterns to identify authorship and register variations.
• They employ statistical, computational, and neural techniques such as n-gram analysis, PCA, and function word adjacency models to discern stylistic features and register-specific patterns.
• Findings reveal distinct markers in human and AI-generated texts, supporting forensic linguistics, content authentication, and cross-register studies.

Stylometric and multidimensional register analyses involve the quantitative evaluation of writing style using linguistic features that capture authorial, genre, and register-based variation. These analyses leverage surface-level metrics (such as function word frequencies and n-grams), syntactic and morphological markers, and, increasingly, multidimensional statistical models to disentangle the complex sources of linguistic variability across individuals, genres, and modes of production. They have found application from uncovering authorial fingerprints and editorial layers to mapping the stylistic constraints and affordances of AI-generated versus human-authored texts.

1. Foundations of Stylometric and Register Analysis

Stylometry quantifies style through measurable linguistic units—lexical, syntactic, morphological, and prosodic. Historically, methods focused on the normalized frequencies of function words, POS n-grams, character n-grams, and morphological affixes as robust, content-independent signals for author attribution, genre discrimination, or register classification.

Multidimensional register analysis operationalizes “register” as a configuration of situationally-conditioned linguistic features, in line with functional definitions (Biber, Conrad) (Argamon, 2019). The multidimensional approach leverages high-dimensional feature vectors, mapping texts into continuous or categorical "register spaces" using statistical techniques such as Principal Component Analysis (PCA) and Factor Analysis. This enables quantitative profiling of registers (e.g., narrative, informational, persuasive) and empirical validation of register theory across languages, text genres, and modalities.

2. Typologies and Extraction of Stylometric Features

A wide variety of linguistic features serve as the basis for stylometric and register analyses, commonly grouped as follows:

Feature Type	Data-Driven Examples	Function in Analysis
Lexical	Most frequent words, hapax legomena, type-token ratio	Captures vocabulary richness, repetition, and word usage patterns
Syntactic	POS n-grams, function word adjacency, parse trees	Encodes grammatical structures and register constraints
Morphological	Character n-grams (e.g., pseudo-affixes), suffix/prefix use	Reflects morphological complexity and stylistic idiosyncrasies
Structural	Sentence/paragraph length, position of punctuation	Indicates discourse structure and organization
Psycholinguistic	Readability indices, emotional valence, subjectivity	Models cognitive and affective aspects
Register-Specific	Repetition, rhythm, foreignness ratio, narrative style	Targets genre or context-dependent stylistic devices (e.g., children’s literature, legalese)

For languages with rich inflection or free word order, features exploiting lemmatization, fine-grained POS segmentation (e.g., “adj:sg”), or affix-based morphology are essential to mitigate data sparsity and accurately recover stylistic markers (Eder et al., 2022).

3. Methodologies: Statistical, Computational, and Neural Techniques

Approaches to stylometric and register analysis span manual feature engineering, statistical modeling, and neural representations:

• Statistical Frequency Analysis: Relative frequency vectors (e.g., of top-k function words) are computed and analyzed using PCA or factor analysis to extract style dimensions (Dentella et al., 22 Aug 2025).
• N-gram and Adjacency Models: Character, word, and POS n-grams are compared using vector similarity metrics (Cosine, Euclidean) to attribute authorship and distinguish stylistic registers (Belvisi et al., 2020). Function Word Adjacency Networks (WANs) model directed transitions between function words, treating stylistic signature as a Markov process with relative entropy as the core similarity metric (Eisen et al., 2016).
• Multidimensional Vector Space Modeling: Multivariate techniques project texts into stylistic spaces (e.g., Biber’s “informational vs. involved production”; "narrative vs. non-narrative” axes) (Argamon, 2019). These latent dimensions are used for both analysis and synthesis of register.
• Neural and Hybrid Models: Modern authorship and register classification increasingly leverage end-to-end neural architectures, either as multi-modal systems combining transformer encoders with hand-crafted features (Shahnazari et al., 27 Jun 2025, Kumarage et al., 2023) or as multitask and metric-learning frameworks (e.g., for structure-aware stylometry in text forums) (Maneriker et al., 2021). Joint optimization and negative sampling enable modality-specific style vectors (topical, lexical, character-level, syntactic) for robust document encapsulation (Ding et al., 2016).
• Explainability and Statistical Hypothesis Testing: Novel frameworks quantify the influence of sequentially correlated properties (e.g., thematic continuity) on classification, separating genuine stylistic signals from sequential artifacts through hypothesis-testing based on empirical autocovariance matrices and surrogate label sequences (Yoffe et al., 7 Nov 2024).

4. Key Findings in Human and AI-Generated Text Analysis

Stylometric and register analyses reveal diagnostic differences between human and AI-generated texts, as well as among registers. Core findings include:

• AI-Generated Texts: Despite increasing sophistication, LLMs display detectable stylometric traits: preference for content words (nouns, nominalizations) over grammaticalized forms (tense, aspect, and mood), reduced function word diversity, and more homogeneous register adaptation (Dentella et al., 22 Aug 2025, Kumarage et al., 2023, Kumarage et al., 2023, Opara, 16 May 2024). Even in contextually adaptive styling, the grammatical backbone of model-generated text remains distinct in function word PCA and multidimensional register analyses.
• Human Authored Texts: Exhibit richer grammatical complexity, wider register variation, and nuanced context-sensitive deployment of grammatical markers. Register shifts induced more robust changes in syntactic patterns and function word usage than those induced in LLM outputs (Dentella et al., 22 Aug 2025).
• Genre, Register, and Language Effects: Analyses of classical poetry, legal, and children’s literature translation demonstrate that stylistic fingerprints persist across languages and genres but require register-sensitive features (meter, narrative structure, playfulness) for full discriminative power (Shahnazari et al., 27 Jun 2025, Kong et al., 27 Jun 2025). In inflected languages, lemmatization does not universally enhance author attribution due to the loss of stylistically salient inflectional morphology (Eder et al., 2022).
• Collaborative and Layered Texts: For historical corpora like Stephen Langton’s Quaestiones Theologiae, concatenation of short texts by stemmatic group and extraction of extended syntactic/morphological feature sets enable identification of editorial layers and distinct collaborative contributions, even with limited sample size (Maliszewski, 18 Aug 2025).

5. Machine Learning, Classification, and Interpretability

Advances in stylometric classification employ both interpretable ensemble methods (e.g., Random Forests, Gradient-Boosted Trees) and deep models. Comprehensive feature sets provide interpretable importance rankings, revealing which signals (e.g., UniqueWordCount, StopWordCount, TTR, function word bigrams) are most influential for distinguishing AI authorship or register (Opara, 16 May 2024, Zaitsu et al., 2023, Ochab et al., 16 Jul 2025).

Cross-validation, stratified sampling, and hyperparameter optimization ensure robust performance across domains, while hybrid approaches leverage both neural semantic embeddings and stylometric vectors to maximize discriminatory power and explicability (Kumarage et al., 2023, Okulska et al., 2023).

Special attention is given to the effect of textual preprocessing; retention of punctuation, contractions, and stopwords improves the sensitivity and reliability of style change and multi-author detection models (Zamir et al., 12 Jan 2024).

6. Applications and Impact

Stylometric and multidimensional register analyses impact:

• Forensic Linguistics and Authorship Attribution: Enabling reliable author verification, identification of layered editorial interventions, and critical assessment of document provenance in both historical and contemporary corpora (Eisen et al., 2016, Yoffe et al., 7 Nov 2024, Maliszewski, 18 Aug 2025).
• AI-Generated Content Detection: Providing quantifiable markers for distinguishing AI- from human-authored texts across genres and languages (including low-resource contexts), supporting academic integrity, digital forensics, and counter-misinformation strategies (Kumarage et al., 2023, Zaitsu et al., 2023, Opara, 16 May 2024, Dentella et al., 22 Aug 2025).
• Cross-Register and Genre Studies: Enabling mapping of functional language varieties, evaluation of translation fidelity (especially in creative or children’s literature), and elucidation of nuanced register-specific patterns in multilingual settings (Argamon, 2019, Kong et al., 27 Jun 2025, Okulska et al., 2023).
• Educational and Psycholinguistic Research: Integrating stylometric features with psycholinguistic theories (cognitive load, lexical access, discourse planning) to elucidate unique cognitive patterns and promote interpretable classification frameworks (Opara, 3 May 2025).

7. Methodological and Theoretical Advances

The integration of robust feature extraction, advanced neural and ensemble classifiers, and multidimensional statistical modeling underpins current methodological best practices. Key innovations include:

• Automated extraction and normalization of rich feature sets that capture both language-specific and cross-linguistic typological aspects, supporting multilingual and cross-genre applications (Okulska et al., 2023, Shahnazari et al., 27 Jun 2025).
• Modular, scalable pipelines allowing for application in both human and AI text forensics and facilitating granular analysis (e.g., scene-by-scene breakdown of collaborative literary works) (Eisen et al., 2016, Maliszewski, 18 Aug 2025).
• Use of hypothesis-testing frameworks to rigorously disentangle stylistic signals from confounding sequential or thematic structures, thereby increasing reliability and interpretability in attribution tasks (Yoffe et al., 7 Nov 2024).
• Interpretability and explainability are prioritized, especially as stylometric analyses increasingly inform high-stakes applications in education, law, and content moderation (Opara, 16 May 2024, Zaitsu et al., 2023).

In conclusion, stylometric and multidimensional register analyses provide a rigorous foundation for quantifying and interpreting linguistic style across diverse communicative contexts, authorial identities, and generative modes. As both feature representations and computational models advance, these analyses will continue to expand the frontiers of authorship attribution, functional linguistics, and the provenance of both human and AI-generated text.