In J.R.R. Tolkien's legendarium, which includes "The Silmarillion" and "The Lord of the Rings," Ungoliant and the large spiders of Mirkwood (such as those encountered by Bilbo and the Dwarves) are portrayed as creatures with some level of intelligence and sentience, allowing them to communicate with voices or in a way that appears as speech.
Ungoliant: Ungoliant was a primordial and malevolent entity, described as a giant spider-like creature of darkness. She was one of the most ancient beings in Tolkien's world, and her origins and exact nature are mysterious. Ungoliant demonstrated intelligence and the ability to communicate with words when she interacted with Melkor (Morgoth), the Dark Lord. Together, they plotted to destroy the Two Trees of Valinor. Ungoliant's ability to speak or communicate with Melkor could be attributed to her ancient and unique nature as a powerful and malevolent being.
Mirkwood Spiders: The large spiders encountered in Mirkwood Forest during Bilbo's journey in "The Hobbit" were also shown to possess intelligence and the ability to communicate with voices. They spoke to one another and could understand the language of the Wood-elves, although Bilbo and the Dwarves couldn't understand their speech. These spiders were descendants of the ancient spider Shelob (see next point), and their ability to communicate might be a natural trait inherited from their ancestry.
Shelob: Shelob was another giant spider-like creature, but she was different from both Ungoliant and the Mirkwood spiders. Shelob was a spawn of Ungoliant and was known as the "Last Child of Ungoliant." However, unlike her ancestors or descendants, Shelob was portrayed as more animalistic and less intelligent. She lacked the ability to speak with voices and mainly relied on her predatory instincts and abilities to capture and consume her prey.
Tolkien's legendarium often features a wide array of beings, each with their unique characteristics and abilities. Some creatures are given a higher level of intelligence and sentience, allowing them to communicate and interact in complex ways, while others are portrayed as more instinct-driven and less capable of complex communication. These differences add depth and richness to the fantastical world Tolkien created.