I can’t complete the requested investigation in the way you asked (i.e., “rely on provided Catholic sources” with citations), because no <references> (Catholic documents) were included with your request. If you paste the relevant <references> set (or specify which Church texts you want used), I can then ground the analysis in Catholic teaching and cite it precisely.

That said, I can still give a scholarly, method-focused analysis of how medieval Latin manuscript “typographic”/layout conventions can shift interpretation, and then state what Catholic principles would require us to do to prevent those shifts from turning into doctrinal errors—without claiming that any particular point is proven by the missing sources.

What “typographic conventions” means in medieval Latin manuscripts

In medieval manuscripts, “typography” is broader than modern fonts. It includes:

• Script features: letterforms and abbreviation practices (e.g., common Latin contraction systems).
• Orthographic conventions: the habitual use of u/v and i/j interchangeably, absence of modern capitalization rules, or inconsistent word separation.
• Layout and segmentation: line breaks, paragraphing by layout rather than punctuation, and the placement of headings or rubrication.
• Punctuation and sign systems: medieval punctuation is often sparse, non-standard, or added later.
• Scholarly apparatus embedded in the page: interlinear glosses, marginal notes, rubricator marks, corrected readings, and decorative/structural signals.

These are not merely “formatting”: they are part of how meaning is encoded on the page.

Mechanisms by which typographic conventions can influence interpretation

Misdivision and resegmentation of text

If word boundaries or sentence boundaries are not visually stabilized (e.g., through spacing or punctuation), a reader may:

• divide a sequence of letters differently,
• assign a clause to the wrong verb,
• or read a modifying phrase as modifying something else.

Doctrinal risk: when a dogmatic conclusion hinges on a specific grammatical relationship (what modifies what), misdivision can make an orthodox line read as heterodox (or vice versa).

Abbreviations and contraction expansion

Medieval shorthand systems (contractions, suspensions, sigla) require expansion choices. Two different expansions can yield different theological terms.

Doctrinal risk: if the expansion changes a key term (or a negation-like element), then the doctrinal proposition can flip. Even when the manuscript is “right,” a typographic convention can induce a plausible alternative reading.

Ligatures and letter-form ambiguity

Some letterform practices (including ligatures) can create ambiguity between:

• similar consonants,
• similar voweling conventions (in unvocalized writing),
• or between forms that modern readers expect to be distinct.

Doctrinal risk: theology can hinge on small lexical differences (e.g., whether a word is positive or negative, whether a predicate is present or absent, etc.).

Punctuation, “pausal” marks, and later editorial markings

Punctuation in medieval manuscripts may be:

• original to the copyist,
• added by a reviser,
• added by a later hand,
• or represented by marks whose function is not always the same as modern punctuation.

Doctrinal risk: shifting where a reader “pauses” can change scope—especially for:

• restrictive phrases,
• causal clauses,
• or phrases that govern the interpretation of an assertion.

Rubrication, headings, and structural signals

Rubrics and headings can reflect:

• the manuscript’s intended organization,
• theological emphasis,
• or a later editor’s interpretation.

Doctrinal risk: readers may treat a heading or marginal structural cue as if it were part of the author’s original semantic intent, when it may reflect later teaching use, catechetical adaptation, or editorial framing.

Glosses and marginalia entering the “main text”

A gloss may be:

• clearly separated (in some manuscripts),
• partially integrated (copyists sometimes assimilate gloss into text),
• or ambiguous in later copies.

Doctrinal risk: a marginal theological explanation can be mistaken as the primary wording, effectively attributing to an author what the glossator actually intended.

Why this matters for doctrinal interpretation

The key Catholic concern (in general terms) is that doctrinal interpretation should be faithful to:

• the substance of the text as intended by its author and
• the regulatory role of the Church’s teaching when controversies arise.

Even if a typographic convention creates multiple plausible readings, doctrinal conclusions should not be built from:

• a visually plausible but textually insecure reading,
• a reading that depends on uncertain abbreviation expansion,
• or a reading that is undermined by manuscript comparison.

So the Catholic “guardrail” (conceptually) is:

• textual integrity first (establish the most warranted reading),
• then interpretive harmony with the Church’s doctrine (and, where applicable, its magisterium and tradition).

A defensible workflow for investigation (what your study should do)

To investigate influence responsibly, you would typically:

1. Catalog the convention (which script feature, abbreviation system, punctuation/sign system, or layout practice is involved).
2. Identify the interpretive variable (which meaning-changing element is at stake: negation, tense/aspect, scope, subject/predicate relations, etc.).
3. Compare manuscripts/recensions (do the variants track the typographic feature, or do they correlate with authorial or transmission changes?).
4. Perform controlled expansions/segmentation tests (show how alternate expansions change the grammar and meaning).
5. Check whether doctrinal claims depend on the fragile detail (if doctrine changes under the alternate reading, that signals a doctrinal method problem, not merely a paleographic curiosity).
6. Evaluate interpretive outcomes against the Church’s doctrinal coherence (do not treat a manuscript typo/variant as decisive for dogma).

Bottom line

Medieval Latin manuscript conventions can influence interpretation by changing the reliable recovery of words and grammatical scope (via abbreviations, segmentation, punctuation/signs, and gloss integration). The doctrinal impact is only legitimate when interpretive conclusions rest on an established and textually warranted reading—not on what the page layout merely makes easy to misread.

If you provide the <references> Catholic sources you want used (or a specific Catholic document about Scripture/text interpretation and doctrine), I can redo this as a source-grounded analysis with direct citations and explicitly connected Catholic principles for doctrinal interpretation.