diff --git a/Cargo.lock b/Cargo.lock
index c2ecdce..3a8336e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -61,7 +61,7 @@ checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
 
 [[package]]
 name = "cargo-i18n"
-version = "0.1.9"
+version = "0.1.10"
 dependencies = [
  "anyhow",
  "clap",
@@ -221,7 +221,7 @@ dependencies = [
 
 [[package]]
 name = "i18n-build"
-version = "0.4.0"
+version = "0.4.1"
 dependencies = [
  "anyhow",
  "gettext",
@@ -249,7 +249,7 @@ dependencies = [
 
 [[package]]
 name = "i18n-embed"
-version = "0.5.0"
+version = "0.6.0"
 dependencies = [
  "doc-comment",
  "fluent-langneg",
diff --git a/Cargo.toml b/Cargo.toml
index 9f89edc..2d5600c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,7 @@ license = "MIT"
 name = "cargo-i18n"
 readme = "README.md"
 repository = "https://github.com/kellpossible/cargo-i18n"
-version = "0.1.9"
+version = "0.1.10"
 
 [badges]
 maintenance = { status = "actively-developed" }
@@ -16,13 +16,13 @@ maintenance = { status = "actively-developed" }
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-i18n-embed = { version = "0.5", path = "./i18n-embed", features = ["desktop-requester"] }
+i18n-embed = { version = "0.6", path = "./i18n-embed", features = ["desktop-requester"] }
 i18n-build = { version = "0.4", path = "./i18n-build", features = ["localize"] }
 i18n-config = { version = "0.2", path = "./i18n-config" }
 anyhow = "1.0"
 gettext = "0.4"
 tr = { version = "0.1", default-features = false, features = ["gettext"] }
-clap = "2.33.0"
+clap = "2.33"
 rust-embed = "5"
 unic-langid = "0.9"
 env_logger = "0.7.1"
diff --git a/i18n-build/CHANGELOG.md b/i18n-build/CHANGELOG.md
index 6fd3809..1ac8769 100644
--- a/i18n-build/CHANGELOG.md
+++ b/i18n-build/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog for `i18n-build`
 
+## v0.4.1
+
++ Update to `i18n-embed` version `0.6.0`.
+
 ## v0.4.0
 
 + Update to `i18n-embed` version `0.5.0`.
diff --git a/i18n-build/Cargo.toml b/i18n-build/Cargo.toml
index f7861b8..edfd40c 100644
--- a/i18n-build/Cargo.toml
+++ b/i18n-build/Cargo.toml
@@ -8,7 +8,7 @@ license = "MIT"
 name = "i18n-build"
 readme = "README.md"
 repository = "https://github.com/kellpossible/cargo-i18n/tree/master/i18n-build"
-version = "0.4.0"
+version = "0.4.1"
 
 [package.metadata.docs.rs]
 all-features = true
@@ -24,7 +24,7 @@ anyhow = "1"
 thiserror = "1"
 tr = { version = "0.1", default-features = false, features = ["gettext"] }
 walkdir = "2"
-i18n-embed = { version = "0.5", path = "../i18n-embed", features = ["desktop-requester"], optional = true }
+i18n-embed = { version = "0.6", path = "../i18n-embed", features = ["desktop-requester"], optional = true }
 i18n-config = { version = "0.2", path = "../i18n-config" }
 gettext = { version = "0.4", optional = true }
 log = "0.4"
diff --git a/i18n-embed/CHANGELOG.md b/i18n-embed/CHANGELOG.md
index 2857c90..f785f07 100644
--- a/i18n-embed/CHANGELOG.md
+++ b/i18n-embed/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog for `i18n-embed`
 
+## v0.6.0
+
++ Changed the argument for `LanguageRequester::add_listener()` to use a `std::rc::Weak` instead of `std::rc::Rc` to make it more obvious that it is the caller's responsibility to hold on to the `Rc` in order to maintain the reference.
++ Fixed typo in `LanguageRequester::set_language_override()`.
+
 ## v0.5.0
 
 + Refactored `I18nEmbedError::Multiple(Box<Vec<I18nEmbedError>>)` to `I18nEmbedError::Multiple(Vec<I18nEmbedError>)`, removing the useless box (and complaining Clippy lint).
diff --git a/i18n-embed/Cargo.toml b/i18n-embed/Cargo.toml
index d1bdd0a..d115d3e 100644
--- a/i18n-embed/Cargo.toml
+++ b/i18n-embed/Cargo.toml
@@ -9,7 +9,7 @@ license = "MIT"
 name = "i18n-embed"
 readme = "README.md"
 repository = "https://github.com/kellpossible/cargo-i18n/tree/master/i18n-embed"
-version = "0.5.0"
+version = "0.6.0"
 
 [package.metadata.docs.rs]
 all-features = true
diff --git a/i18n-embed/src/lib.rs b/i18n-embed/src/lib.rs
index 78915a7..8444d62 100644
--- a/i18n-embed/src/lib.rs
+++ b/i18n-embed/src/lib.rs
@@ -107,7 +107,7 @@
 //!     let localizer_rc: Rc<dyn Localizer> = Rc::new(localizer);
 //!
 //!     let mut language_requester = DesktopLanguageRequester::new();
-//!     language_requester.add_listener(&localizer_rc);
+//!     language_requester.add_listener(Rc::downgrade(&localizer_rc));
 //!
 //!     // Manually check the currently requested system language,
 //!     // and update the listeners. When the system language changes,
@@ -239,7 +239,10 @@ extern crate i18n_embed_impl;
 pub use i18n_embed_impl::*;
 
 use std::borrow::Cow;
-use std::rc::{Rc, Weak};
+use std::{
+    collections::{HashMap, HashSet},
+    rc::Weak,
+};
 
 use fluent_langneg::{negotiate_languages, NegotiationStrategy};
 use log::{debug, error, info};
@@ -340,7 +343,7 @@ impl<'a> LanguageRequesterImpl<'a> {
     /// Set an override for the requested language which is used when the
     /// [LanguageRequesterImpl#poll()](LanguageRequester#poll()) method
     /// is called. If `None`, then no override is used.
-    fn set_languge_override(
+    fn set_language_override(
         &mut self,
         language_override: Option<unic_langid::LanguageIdentifier>,
     ) -> Result<(), I18nEmbedError> {
@@ -348,8 +351,8 @@ impl<'a> LanguageRequesterImpl<'a> {
         Ok(())
     }
 
-    fn add_listener(&mut self, localizer: &Rc<dyn Localizer<'a>>) {
-        self.listeners.push(Rc::downgrade(localizer));
+    fn add_listener(&mut self, localizer: Weak<dyn Localizer<'a>>) {
+        self.listeners.push(localizer);
     }
 
     /// With the provided `requested_languages` call
@@ -387,7 +390,7 @@ impl<'a> LanguageRequesterImpl<'a> {
     /// With the provided `requested_languages` call
     /// [Localizer#select()](Localizer#select()) on each of the
     /// listeners. The `requested_languages` may be ignored if
-    /// [#set_languge_override()](#set_languge_override()) has been
+    /// [#set_language_override()](#set_language_override()) has been
     /// set.
     pub fn poll(
         &mut self,
@@ -403,6 +406,36 @@ impl<'a> LanguageRequesterImpl<'a> {
 
         self.poll_without_override(languages)
     }
+
+    /// The languages reported to be available in the
+    /// listener [Localizer](Localizer)s.
+    fn available_languages(&self) -> Result<Vec<unic_langid::LanguageIdentifier>, I18nEmbedError> {
+        let mut available_languages = HashSet::new();
+        for weak_listener in &self.listeners {
+            if let Some(localizer) = weak_listener.upgrade() {
+                localizer
+                    .available_languages()?
+                    .iter()
+                    .for_each(|language| {
+                        available_languages.insert(language.clone());
+                    })
+            }
+        }
+
+        Ok(available_languages.into_iter().collect())
+    }
+
+    fn current_languages(&self) -> HashMap<&'static str, unic_langid::LanguageIdentifier> {
+        let mut current_languages = HashMap::new();
+        for weak_listener in &self.listeners {
+            if let Some(localizer) = weak_listener.upgrade() {
+                let loader = localizer.language_loader();
+                current_languages.insert(loader.domain(), loader.current_language());
+            }
+        }
+
+        current_languages
+    }
 }
 
 /// A trait used by [I18nEmbed](I18nEmbed) to ascertain which
@@ -416,31 +449,25 @@ pub trait LanguageRequester<'a> {
     /// If you haven't already selected a language for the localizer
     /// you are adding here, you may want to manually call
     /// [#poll()](#poll()) after adding the listener/s.
-    fn add_listener(&mut self, localizer: &Rc<dyn Localizer<'a>>);
+    fn add_listener(&mut self, localizer: Weak<dyn Localizer<'a>>);
     /// Poll the system's currently selected language, and call
     /// [Localizer#select()](Localizer#select()) on each of the
     /// listeners.
     fn poll(&mut self) -> Result<(), I18nEmbedError>;
     /// Override the languages fed to the [Localizer](Localizer) listeners during
     /// a [#poll()](#poll()). Set this as `None` to disable the override.
-    fn set_languge_override(
+    fn set_language_override(
         &mut self,
         language_override: Option<unic_langid::LanguageIdentifier>,
     ) -> Result<(), I18nEmbedError>;
-    /// Get the language last selected for the [LanguageLoader](LanguageLoader)
-    /// by this [LanguageRequester](LanguageRequester).
-    // fn currently_selected_language(&self, language_loader: &'a dyn LanguageLoader) -> &Option<unic_langid::LanguageIdentifier>;
-    // fn override_request(&self, language_id: unic_langid::LanguageIdentifier);
-    // fn reset_override_request(&self);
-    // /// Attach a listener to the system this requester is mediating
-    // /// for, to listen for changes, and trigger a language update if
-    // /// required.
-    // fn attach_system_listener(&self) -> Result<(), Box<dyn std::error::Error>>;
-    // /// Detach the listener which was attached using
-    // /// [attach_change_listener()](#attach_change_lister()).
-    // fn detatch_system_listener(&self) -> Result<(), Box<dyn std::error::Error>>;
     /// The currently requested languages.
     fn requested_languages(&self) -> Vec<unic_langid::LanguageIdentifier>;
+    /// The languages reported to be available in the
+    /// listener [Localizer](Localizer)s.
+    fn available_languages(&self) -> Result<Vec<unic_langid::LanguageIdentifier>, I18nEmbedError>;
+    /// The languages currently loaded, keyed by the
+    /// [LanguageLoader::domain()](LanguageLoader::domain()).
+    fn current_languages(&self) -> HashMap<&'static str, unic_langid::LanguageIdentifier>;
 }
 
 /// Select the most suitable language currently requested by the
@@ -655,20 +682,28 @@ impl<'a> LanguageRequester<'a> for DesktopLanguageRequester<'a> {
         Self::requested_languages()
     }
 
-    fn add_listener(&mut self, localizer: &Rc<dyn Localizer<'a>>) {
+    fn add_listener(&mut self, localizer: Weak<dyn Localizer<'a>>) {
         self.implementation.add_listener(localizer)
     }
 
-    fn set_languge_override(
+    fn set_language_override(
         &mut self,
         language_override: Option<unic_langid::LanguageIdentifier>,
     ) -> Result<(), I18nEmbedError> {
-        self.implementation.set_languge_override(language_override)
+        self.implementation.set_language_override(language_override)
     }
 
     fn poll(&mut self) -> Result<(), I18nEmbedError> {
         self.implementation.poll(self.requested_languages())
     }
+
+    fn available_languages(&self) -> Result<Vec<unic_langid::LanguageIdentifier>, I18nEmbedError> {
+        self.implementation.available_languages()
+    }
+
+    fn current_languages(&self) -> HashMap<&'static str, unic_langid::LanguageIdentifier> {
+        self.implementation.current_languages()
+    }
 }
 
 #[cfg(feature = "desktop-requester")]
@@ -747,7 +782,7 @@ impl<'a> LanguageRequester<'a> for WebLanguageRequester<'a> {
         Self::requested_languages()
     }
 
-    fn add_listener(&mut self, localizer: &Rc<dyn Localizer<'a>>) {
+    fn add_listener(&mut self, localizer: Weak<dyn Localizer<'a>>) {
         self.implementation.add_listener(localizer)
     }
 
@@ -755,11 +790,19 @@ impl<'a> LanguageRequester<'a> for WebLanguageRequester<'a> {
         self.implementation.poll(self.requested_languages())
     }
 
-    fn set_languge_override(
+    fn set_language_override(
         &mut self,
         language_override: Option<unic_langid::LanguageIdentifier>,
     ) -> Result<(), I18nEmbedError> {
-        self.implementation.set_languge_override(language_override)
+        self.implementation.set_language_override(language_override)
+    }
+
+    fn available_languages(&self) -> Result<Vec<unic_langid::LanguageIdentifier>, I18nEmbedError> {
+        self.implementation.available_languages()
+    }
+
+    fn current_languages(&self) -> HashMap<&'static str, unic_langid::LanguageIdentifier> {
+        self.implementation.current_languages()
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index dd92049..ef90b6e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -81,8 +81,8 @@ fn main() -> Result<()> {
     let cargo_i18n_localizer_rc: Rc<dyn Localizer> = Rc::new(cargo_i18n_localizer);
     let i18n_build_localizer_rc = Rc::new(i18n_build::localizer()) as Rc<dyn Localizer<'static>>;
 
-    language_requester.add_listener(&cargo_i18n_localizer_rc);
-    language_requester.add_listener(&i18n_build_localizer_rc);
+    language_requester.add_listener(Rc::downgrade(&cargo_i18n_localizer_rc));
+    language_requester.add_listener(Rc::downgrade(&i18n_build_localizer_rc));
     language_requester.poll()?;
 
     let src_locale = LANGUAGE_LOADER.src_locale().to_string();
@@ -150,7 +150,7 @@ fn main() -> Result<()> {
             .expect("expected a default language to be present");
 
         let li: LanguageIdentifier = language.parse()?;
-        language_requester.set_languge_override(Some(li))?;
+        language_requester.set_language_override(Some(li))?;
         language_requester.poll()?;
 
         let path = i18n_matches