diff --git a/DESCRIPTION b/DESCRIPTION
index ac3e51ac..c003cdd6 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,6 +1,6 @@
 Package: sandpaper
 Title: Create and Curate Carpentries Lessons
-Version: 0.16.1.9000
+Version: 0.16.2
 Authors@R: c(
     person(given = "Zhian N.",
            family = "Kamvar",
diff --git a/NEWS.md b/NEWS.md
index 45d3ef46..c9c79de6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,4 +1,8 @@
-# sandpaper 0.16.1.9000 (unreleased)
+# sandpaper 0.16.2 (2023-12-19)
+
+## MISC
+
+* JSON metadata now contains the `inLanguage` key.
 
 ## DOCUMENTATION
 
diff --git a/R/utils-metadata.R b/R/utils-metadata.R
index bd50e7cf..a941c4b9 100644
--- a/R/utils-metadata.R
+++ b/R/utils-metadata.R
@@ -13,6 +13,7 @@ fill_metadata_template <- function(meta) {
   if (endsWith(local_meta$url, "/")) {
     local_meta$url <- paste0(local_meta$url, "index.html")
   }
+  local_meta$lang <- sub("_", "-", local_meta$lang %||% "en")
   title <- local_meta$pagetitle
   if (grepl("<", title, fixed = TRUE)) {
     local_meta$pagetitle <- xml2::xml_text(xml2::read_html(title))
diff --git a/inst/templates/metadata-template.txt b/inst/templates/metadata-template.txt
index 7aeee275..d205d566 100644
--- a/inst/templates/metadata-template.txt
+++ b/inst/templates/metadata-template.txt
@@ -3,6 +3,7 @@
   "@context": "https://schema.org",
   "@type": "TrainingMaterial",
   "@id": "<% url %>",
+  "inLanguage": "<% lang %>",
   "dct:conformsTo": "https://bioschemas.org/profiles/TrainingMaterial/1.0-RELEASE",
   "description": "<% desc %><% ^desc %>A Carpentries Lesson teaching foundational data and coding skills to researchers worldwide<% /desc %>",
   "keywords": "<% keywords %><% ^keywords %>software,data,lesson,The Carpentries<% /keywords %>",
diff --git a/tests/testthat/_snaps/utils-metadata.md b/tests/testthat/_snaps/utils-metadata.md
index 19853540..4ae58569 100644
--- a/tests/testthat/_snaps/utils-metadata.md
+++ b/tests/testthat/_snaps/utils-metadata.md
@@ -1,4 +1,4 @@
 # metadata can be initialised with custom items added 
 
-    "{\n  \"@context\": \"https://schema.org\",\n  \"@type\": \"TrainingMaterial\",\n  \"@id\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"dct:conformsTo\": \"https://bioschemas.org/profiles/TrainingMaterial/1.0-RELEASE\",\n  \"description\": \"A Carpentries Lesson teaching foundational data and coding skills to researchers worldwide\",\n  \"keywords\": \"software, data, lesson, The Carpentries\",\n  \"name\": \"The Importance of Being Ernest Scared Stupid\",\n  \"creativeWorkStatus\": \"active\",\n  \"url\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"identifier\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"dateCreated\": \"2022-02-01\",\n  \"dateModified\": \"2022-02-08\",\n  \"datePublished\": \"2022-02-09\"\n}\n"
+    "{\n  \"@context\": \"https://schema.org\",\n  \"@type\": \"TrainingMaterial\",\n  \"@id\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"inLanguage\": \"en\",\n  \"dct:conformsTo\": \"https://bioschemas.org/profiles/TrainingMaterial/1.0-RELEASE\",\n  \"description\": \"A Carpentries Lesson teaching foundational data and coding skills to researchers worldwide\",\n  \"keywords\": \"software, data, lesson, The Carpentries\",\n  \"name\": \"The Importance of Being Ernest Scared Stupid\",\n  \"creativeWorkStatus\": \"active\",\n  \"url\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"identifier\": \"https://zkamvar.github.io/lesson-example/vern.html\",\n  \"dateCreated\": \"2022-02-01\",\n  \"dateModified\": \"2022-02-08\",\n  \"datePublished\": \"2022-02-09\"\n}\n"
 
diff --git a/tests/testthat/test-utils-metadata.R b/tests/testthat/test-utils-metadata.R
index 783571f7..6831c1ea 100644
--- a/tests/testthat/test-utils-metadata.R
+++ b/tests/testthat/test-utils-metadata.R
@@ -18,16 +18,27 @@ test_that("metadata can be initialised with custom items added ", {
   on.exit(this_metadata$clear())
   # metadata has same values as config
   expect_equal(this_metadata$get()[["carpentry"]], "incubator")
-  met <- create_metadata_jsonld(res, 
+  met <- create_metadata_jsonld(res,
     date = list(created = "2022-02-01", modified = "2022-02-08", published = "2022-02-09"),
     pagetitle = "The Importance of Being Ernest Scared Stupid",
     url = "https://zkamvar.github.io/lesson-example/vern.html"
   )
   expect_type(met, "character")
   expect_match(met, "Ernest Scared Stupid")
+  expect_match(met, "\"inLanguage\": \"en\"", fixed = TRUE)
   expect_length(met, 1L)
   skip_on_os("windows") # dang carriage returns
   expect_snapshot_value(met)
+
+  met <- create_metadata_jsonld(res,
+    pagetitle = "The Importance of Being Ernest Scared Stupid",
+    url = "https://zkamvar.github.io/lesson-example/vern.html",
+    lang = "es_AR"
+  )
+  expect_type(met, "character")
+  expect_match(met, "Ernest Scared Stupid")
+  expect_match(met, "\"inLanguage\": \"es-AR\"", fixed = TRUE)
+  expect_length(met, 1L)
 })