hreflang is how a site with several language versions tells an assistant which one to quote to which reader. A site with one language has nothing to declare.
Structure — Is the important data machine-readable instead of implied by visual layout?
Weight within the pillar
4 points
Share of the overall score
about 0.8 of 100
Kind of change
Engineering — a code change and a deploy
Two numbers rather than one, because a check's weight is inside its pillar and the pillar is a share
of the whole. The largest check in the smallest pillar moves your score less than a middling one in
the largest, and knowing which you are looking at is the difference between fixing the right thing
and fixing the loudest thing.
Why an agent cares
hreflang is how a site with several language versions tells an assistant which one to quote to which reader. A site with one language has nothing to declare.
Worth saying plainly: this is not a search-engine ranking factor and passing it will not move you up
a results page. It measures something else — whether software with no browser, no JavaScript
and a few hundred tokens of budget can tell what your page is and do something with it. Those are the
conditions an AI assistant reads you under, and they are much harsher than a browser's.
How to satisfy it
This check does not carry a copy-pasteable snippet, and the reason is worth stating rather than
papering over: what it measures is a property of your server or your whole document, not a tag that
can be pasted into it. hreflang is how a site with several language versions tells an assistant which one to quote to which reader. A site with one language has nothing to declare.
Scan the page and the report will say what was actually observed — the header that was missing,
the status that came back, the passage that could not stand alone — which is the part that tells
you what to change. A generic snippet here would be a guess about a site nobody has looked at.
How often the web fails this
Measured on 2026-09-06 against AX specification v1.5.1, across a
sample of 292 public websites.
Result
Sites
Share of those assessed
Failed
0
0%
Warned
16
17%
Passed
77
83%
Did not apply
199
excluded from the shares
The last row is kept out of the percentages deliberately. A check that did not apply to
199 of 292 sites is not a check most of the web passes, and folding those in is the
commonest way this sort of table is used to say something untrue.
At 0% this is something most sites already get right, which makes failing it more costly than the point value suggests — you are behind the field rather than level with it.
Testing it on your own site
npx axray-cli your-site.com
All 70 checks against one URL, this one among them, with what was found rather than only whether it
passed. Add --min 70 in a pipeline and the command exits non-zero below that score, so a
change that breaks what agents can read fails the build instead of shipping.
Questions about this check
What does the "Declares its language alternates" check mean?
hreflang is how a site with several language versions tells an assistant which one to quote to which reader. A site with one language has nothing to declare. It sits in the Structure pillar of the Agent Experience rubric and is worth 4 points within that pillar, which works out at about 0.8 points of the overall score out of 100.
Is it unusual to fail language-alternates?
No. Of 93 public sites where this check applied, 0 failed it — 0%. The measurement was taken on 2026-09-06 against AX specification v1.5.1, and no site is named.
How do I test language-alternates on my own site?
Run npx axray-cli your-site.com from a terminal. It runs all 70 checks against one URL and prints this one among them, with what it found rather than only whether it passed. It is free, needs no account and installs nothing.
The rest of the Structure pillar
Is the important data machine-readable instead of implied by visual layout?