Bilingual books, native text on one page or column and a translation on the facing one, get recommended constantly for language learners, and the answer to whether they help isn't a simple yes or no. It depends heavily on how you actually use the translation column, and the honest answer is that the same book can genuinely accelerate one learner's reading and quietly stall another's, depending on a habit that has nothing to do with which book they bought.
The real case for parallel text
The legitimate benefit of parallel text is removing the interruption cost of looking something up. Reading real text without a translation nearby means every unfamiliar word or confusing sentence either breaks your reading flow to check a dictionary or gets skipped, guessed at, and possibly misunderstood. A translation sitting right next to the original removes that friction: you can glance over, confirm a meaning, and keep reading, which lets you get through more real, native-level text than you might otherwise attempt at your current level, since the safety net of the translation makes harder material feel more approachable.
This matters specifically because volume of real exposure is a genuine driver of reading comprehension growth. A learner who can push through more real sentences, even leaning on a translation occasionally, is getting real exposure to real vocabulary and structure they might otherwise avoid as too difficult, which has real value independent of whether every individual glance at the translation was strictly necessary.
Where it becomes a crutch instead of a scaffold
The problem isn't the translation existing. It's how automatically your eyes go to it. If checking the translation becomes the reflexive first move whenever a sentence takes half a second longer than expected, rather than a deliberate choice made after actually attempting the original, the translation stops functioning as a safety net and starts functioning as the primary route to meaning, with the native-language text becoming a formality your eyes pass over on the way to the column that actually tells you what's happening.
This connects directly to the broader problem of mental translation slowing reading down: a bilingual text used this way trains exactly the habit that a strong reader needs to move away from, routing every sentence through the native language rather than building direct comprehension. Worse, it can reinforce the habit more strongly than mental translation alone would, because the translation is sitting right there, fully worked out, requiring no retrieval effort of your own at all, which is an even easier habit to fall into than translating in your own head.
A practical way to tell which one is happening to you
Read a sentence in the target-language column and consciously commit to an attempt at understanding it, even a rough or partial one, before your eyes are allowed to move to the translation. If you can usually produce a reasonable attempt first and the translation mostly confirms or slightly corrects it, the parallel text is functioning as a scaffold, doing exactly what it's supposed to do. If your honest answer is that you rarely attempt the original first, that your eyes go straight to the translation by habit, that's the sign the crutch has taken over, and it's worth deliberately changing how you're reading the same material, not necessarily abandoning parallel text altogether.
A middle path that keeps the benefit without the cost
One workable approach is reading a full passage in the target language first, genuinely attempting it without looking at the translation at all, and only then checking the facing page to see what you got right, wrong, or missed entirely. This preserves the volume-and-approachability benefit of having a safety net available, since a genuinely stuck reader can still consult it, while removing the reflexive, low-effort habit of using the translation as the first and only route to meaning. It also turns the translation into a form of feedback, showing you specifically where your independent comprehension broke down, which is more useful for improvement than a translation you never really had to test yourself against in the first place.
Interlinear versus side-by-side formats matter too
Not all parallel text is built the same way, and the format itself changes how easy the crutch habit is to fall into. A side-by-side format, native language on one full page and the translation on the facing page, requires a real eye movement and a moment of searching to find the corresponding line, which creates just enough friction to make a genuine attempt at the original the path of least resistance for a reasonably motivated reader. An interlinear format, where a translation sits directly under or beside each individual line or even each word, removes almost all of that friction, since the translation is right there in your peripheral vision without any deliberate movement required to find it. Interlinear formats are genuinely useful for absolute beginners working through their first few real texts, where the goal is simply building enough vocabulary and structural familiarity to attempt independent reading at all. Past that early stage, the near-zero friction of an interlinear format makes the reflexive-glance habit considerably easier to fall into than a side-by-side layout does, which is worth knowing before choosing which format to build a longer-term reading habit around.
What this means for choosing material
Parallel text is a reasonable tool at any stage, but its usefulness depends on discipline more than on the format itself. A genuinely disciplined reader can get real value from bilingual editions well into an advanced stage, using the translation as an occasional check rather than a constant companion. A less disciplined reader, at any level, is often better served by reading material calibrated to be independently manageable at their level, without a translation, the same underlying principle behind choosing text you can process largely without stopping at every unfamiliar word, where the goal is building tolerance for gaps and direct comprehension, not eliminating the need for either through a translation sitting one glance away.