Is there any difference between "word-for-word translation" and "word-by-word translation" and is the latter actually valid?

Question

First off, some data:

According to COCA word-for-word has 60 usages, 3 of them are "word-for-word translation". Word-by-word has 26 usages, none of them are "word-by-word translation" (but some with "transcription").

The definition of word-for-word:

Oxford: In exactly the same or, when translated, exactly equivalent words
Merriam-Webster: being in or following the exact words, verbatim
The Free Dictionary: one word at a time, without regard for the sense of the whole

Only the last dictionary contains a definition for word-by-word, too:

The Free Dictionary: one word at a time

The definitions given by The Free Dictionary are, obviously, identical to each other.

Google hits:
Word-for-word ~21m
Word-for-word translation ~318k
Word-by-word ~3.8m
Word-by-word translation ~95k

According to usages and dictionaries word-by-word is, at least, less popular. And assuming that there may be a lot of usages from non-natives among the Google hits, this could be an indicator for word-by-word being even utterly wrong.

In another forum I found the following statement:

When I translate something "literally," (wörtlich) it still follows the main rules of the language I'm translating into. What you mean is "word-by-word" (wortwörtlich) to me.

I assume that this was written by a German but I don't know it. However, if this would be true a "word-by-word translation" would be a translation where I keep, for instance, the order of the words, disregarding if it makes sense in the target language.

Some examples:

Original: word-by-word
Word-by-word translation: Wort bei Wort (That's a terrible translation!)

Original: It is critical to know...
Word-by-word translation: Es ist kritisch zu wissen... (That's a terrible translation!)

Original: Ich glaub, ich spinne.
Word-by-word translation: I think I spider. (I guess only Germans understand this.)

A "word-for-word translation", however, would be an attempt to keep the word-choice as close as possible but following the rules of the target language (e.g. order of words) and also considering if the statement still makes sense in the other language. Here are better translations for the examples above:

Wort für Wort
Es ist wichtig zu wissen...
I think, I'm going nuts. (Actually, this is not a word-for-word translation but rather a sense-for-sense translation.)

So, my questions again:

1. As neither Oxford nor Merriam-Webster have any entries for word-by-word in their dictionaries: is word-by-word actually valid?
2. If yes, is there any difference between "word-by-word translation" and "word-for-word translation"? If yes again, what is it specifically?

Answer 1

The standard idiom word for word doesn't particularly relate to "translation" contexts at all. It's about accurately copied/reported words, as in the book title...

Elvis: Word for Word
What you'll read are Elvis's words and only Elvis's words. From his first minor radio appearance to the last letter he wrote before his death...

In a translation context, such as this page explaining the French expression...

Appeler un chat un chat
Meaning: to call a spade a spade, to be honest and frank, to tell it like it is
Literal translation: to call a cat a cat

...we're much more likely to describe the "exact" translation as literal, not word-for-word.

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There are no dictionary definitions for word by word, because it's not an idiom as such - it's just one possible form of the X by X construction (a succession of consecctive X's)...

Foot by foot, and house by house, the enemy were driven in towards the Plaza.
Day by day he worked on, and day by day the postman delivered to him rejected manuscripts.
Book by book, he decimates the Bible for factual errors and internal contradictions.

It's perfectly possible to translate "word by word" or "word for word". Of those two, the second is about ten times more common, but I see no reason to suppose there could ever be a difference in meaning. Overall though, there are far more written references to "literally translated" and similar variations.

Answer 2

As you and others have noted, a word-by-word translation, if taken literally, would entail taking each word of the source text and translating it individually into the target language. This is a terrible idea, as it would make mincemeat of idioms and synonyms, and would likely produce incomprehensible results for most texts longer than two or three words. It is therefore likely that any occurrence of "word-by-word translation" are mistakes resulting from someone conflating "word-for-word" with the familiar X by X construction.

edit: As FumbleFingers correctly notes, "word-for-word translation" is also nonsense if taken word-for-word--sorry, I mean if taken literally. As I have very cleverly shown, though, the phrase word for word is itself used idiomatically as a synonym for literal, whereas word by word is not. (Did I say "cleverly"? Sorry, I meant "clumsily.") So I believe "word-for-word translation" would be more likely to be read idiomatically as meaning "literal translation," while "word-by-word translation" lacks this idiomatic sense and forces the audience to consider it at face value. Really, though, you should just avoid using either one.

Answer 3

Word-for-word - translate each word/phrase for its equivalent in the target language; retain meaning of sentence at expense of loss of precise idiom ("Ich glaub, ich spinne" becomes "I think I am going mad"; the sentiment is retained at the loss of the idiom).

Word-by-word - translate each word to its closest match, overall expression retained, at possible cost of meaning ("Ich glaub, ich spinne" becomes "I think I spider"; the idiom is retained at the likely loss of the sentiment).

Both are valid expressions but as you have indicated, they mean different things.

Ich glaub, ich spinne is an injoke between my German friends and I, so I would personally understand you without consideration either way!

Answer 4

'Word for word'means 'verbatim.' Word by word means 'taking it one word at a time.' (NTC's American Idioms Dictionary) The latter phrase is valid.