diff --git a/src/backends/av_foundation.rs b/src/backends/av_foundation.rs
index bdd5620..e097b1e 100644
--- a/src/backends/av_foundation.rs
+++ b/src/backends/av_foundation.rs
@@ -6,13 +6,14 @@ use cocoa_foundation::base::{id, nil};
 use cocoa_foundation::foundation::NSString;
 use lazy_static::lazy_static;
 use log::{info, trace};
-use objc::runtime::*;
-use objc::*;
+use objc::runtime::{Object, Sel};
+use objc::{class, declare::ClassDecl, msg_send, sel, sel_impl};
 
-use crate::{Backend, BackendId, Error, Features, UtteranceId};
+use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
 pub(crate) struct AvFoundation {
     id: BackendId,
+    delegate: *mut Object,
     synth: *mut Object,
     rate: f32,
     volume: f32,
@@ -26,11 +27,71 @@ lazy_static! {
 impl AvFoundation {
     pub(crate) fn new() -> Self {
         info!("Initializing AVFoundation backend");
+        let mut decl = ClassDecl::new("MyNSSpeechSynthesizerDelegate", class!(NSObject)).unwrap();
+        decl.add_ivar::<u64>("backend_id");
+
+        extern "C" fn speech_synthesizer_did_start_speech_utterance(
+            this: &Object,
+            _: Sel,
+            synth: *const Object,
+            utterance: id,
+        ) {
+            unsafe {
+                let backend_id: u64 = *this.get_ivar("backend_id");
+                let backend_id = BackendId::AvFoundation(backend_id);
+                let callbacks = CALLBACKS.lock().unwrap();
+                let callbacks = callbacks.get(&backend_id).unwrap();
+                if let Some(callback) = callbacks.utterance_begin {
+                    let utterance_id = UtteranceId::AvFoundation(utterance);
+                    callback(utterance_id);
+                }
+            }
+        }
+
+        extern "C" fn speech_synthesizer_did_finish_speech_utterance(
+            this: &Object,
+            _: Sel,
+            synth: *const Object,
+            utterance: id,
+        ) {
+            unsafe {
+                let backend_id: u64 = *this.get_ivar("backend_id");
+                let backend_id = BackendId::AvFoundation(backend_id);
+                let callbacks = CALLBACKS.lock().unwrap();
+                let callbacks = callbacks.get(&backend_id).unwrap();
+                if let Some(callback) = callbacks.utterance_end {
+                    let utterance_id = UtteranceId::AvFoundation(utterance);
+                    callback(utterance_id);
+                }
+            }
+        }
+
+        unsafe {
+            decl.add_method(
+                sel!(speechSynthesizer:didStartSpeechUtterance:),
+                speech_synthesizer_did_start_speech_utterance
+                    as extern "C" fn(&Object, Sel, *const Object, id) -> (),
+            );
+            decl.add_method(
+                sel!(speechSynthesizer:didFinishSpeechUtterance:),
+                speech_synthesizer_did_finish_speech_utterance
+                    as extern "C" fn(&Object, Sel, *const Object, id) -> (),
+            );
+        }
+
+        let delegate_class = decl.register();
+        let delegate_obj: *mut Object = unsafe { msg_send![delegate_class, new] };
         let mut backend_id = NEXT_BACKEND_ID.lock().unwrap();
         let rv = unsafe {
             let synth: *mut Object = msg_send![class!(AVSpeechSynthesizer), new];
+            delegate_obj
+                .as_mut()
+                .unwrap()
+                .set_ivar("backend_id", *backend_id);
+            let _: () = msg_send![synth, setDelegate: delegate_obj];
             AvFoundation {
                 id: BackendId::AvFoundation(*backend_id),
+                delegate: delegate_obj,
                 synth: synth,
                 rate: 0.5,
                 volume: 1.,
@@ -157,6 +218,7 @@ impl Backend for AvFoundation {
 impl Drop for AvFoundation {
     fn drop(&mut self) {
         unsafe {
+            let _: Object = msg_send![self.delegate, release];
             let _: Object = msg_send![self.synth, release];
         }
     }