English line breaking rules

Solution 1:

In English you can have a line break at any point in a sentence, it is not restricted by nouns, verbs, prepositions, etc. The only restrictions I have come across are the ones pointed out by @Gnawme, the "widows" and "orphans", but those rules are aesthetic and not grammatical.

Solution 2:

Though meant for creating subtitles for foreign users, this link of TED was quite informative for my purposes—deciding line breaks for two/three-line-per-page stories for children. It’s less grammar based and more aesthetic based.

A few important rules I understand from above are:

• Do not break up linguistic units among lines.
• Maintain balance, similar length, between multiple lines. Maintaining line-length balance is more important than keep linguistic units together.
• When absolutely necessary to keep linguistic units together (like a person’s name), then the line break should still not cause a line to be more than 50% shorter than the other line.

Further quotes from above link:

• The articles (a, an, the) are never followed by a line break.

• An adjective should stay together with what it is describing, but two or more adjectives can sometimes be separated with commas, and then it is possible (though not preferable) to break a line after one of the commas.

• Clauses should stay together (never break lines after relative pronouns like which, that, who, etc.).

• Prepositions are not followed by a line break if the break would separate them from the noun they refer to. A preposition in a concrete/physical meaning (e.g. "The book is in the drawer") always precedes a noun, and cannot be followed by a line break. However, in English, a preposition that is part of a phrasal verb (put up, figure out, take in) may sometimes not be followed by a noun ("I figured it out yesterday"), and so, it can be followed by a line break.

• Proper names should stay together if at all possible (think of them as a single word with many parts).

Grammatical style guides don’t seem to cover the rules for line breaks, but another link might help

Important paragraph from above-mentioned link:

Oxford says in page 140 that "Do not carry over parts of abbreviations, dates, or numbers to the next line", "Do not break numbers at a decimal point, or separate them from their abbreviated units, as with 15 kg or 300 BC. If unavoidable large numbers may be broken (but not hyphenated) at their comma, though not after a single digit: 493,|000,|000."

Solution 3:

A concern for typographers in almost any language (typography is a visual art, after all) is avoiding widows and orphans. As this site explains:

A widow is a short line or single word at the end of a paragraph. An orphan is a word or short line at the beginning or end of a column that is separated from the rest of the paragraph. Widows and Orphans create awkward rags, interrupt the reader’s eye and affect readability. They can be avoided by adjusting the type size, leading, measure, wordspacing, letterspacing or by entering manual line breaks.

Not paying attention to this detail might make for awkward, if not erroneous, reading -- imagine if you left a key word in a paragraph a widow, and the page break was such that the widow ended up on a separate page -- but it wouldn't cause grammatical errors in English.