According to the latest information from the Android engineering team indicates that T-Mobile G1 smartphone will be able to load the “Android 1.6” firmware update after all.
According to AndroidGuys citing the official Android for Developers blog, the 1.6 firmware page specifically mentions the new text-to-speech feature in conjunction with the G1, strongly indicating that the device will be able to run Android 1.6 after all. The New Platform Technologies section at the official Android for Developers blog says the following:
Android 1.6 features a multi-lingual speech synthesis engine called Pico. It allows any Android application to “speak” a string of text with an accent that matches the language. The engine supports the following languages: English (American and British accents), French, Italian, German and Spanish. If you’re using a T-Mobile G1 or Dream device, you’ll need to download the SpeechSynthesis Data Installer from Android Market, which includes the “voices” needed by the text-to-speech engine.